R/B/Y
These were the first games in the series that I played so I should logically have some strong memories regarding the music from them. But I don't. Guess I have forgotten much of it. But there are some I remember at least, though I don't have that much to say about them. Overall, I do remember the soundtrack as being good for its time at least, but hardly the best in the series.
Vermilion City - One of my favorites that I really can remember, a great and powerful energetic track that quickly became my one of my favorites.
Route 24/25 - I just really like the melody here, and it felt like a good closing tune since Route 25 is a dead end and the last Kanto Route going by numbers.
S.S. Anne - Another one I like the melody of, I can get easily attached to bittersweet/melancholic songs if they are done correctly. Like this. I remember how I thought the boat would return if I waited a whole year...
G/S/C
A bit different than last generation as I can remember more this time around as there were a few songs that I really liked. Another good soundtrack for its time, though I feel it is rather overrated by the fandom. Favorites are the following:
Goldenrod City, one of the best city themes, just relaxing in a not too happy way which I liked. I remember spending lots of time in Goldenrod, doing nothing but listening to the music because I liked it so much. However, I didn't like the remake version at all because it ruined the feel of the original for me by being way too happy.
Route 42, 43, 44 & Lake of Rage. Wonderful. Like Goldenrod, I often went to these areas just to hear the music here. This has a kind of epic feel which I like, or something like that. Great melody too.
Raikou/Entei/Suicune Battle Theme. The first time legendaries got their own battle theme, and it was amazing. Suits them perfectly. Really wish I had been able to hear this more often, after catching Suicune I didn't bother that much with Raikou and Entei. Got to hear it more in the remakes at least.
R/S/E
A wonderful soundtrack, overall better quality by modern standards compared to the previous two. Emerald is my favorite game from this generation, and it has several exclusive tracks that R/S lacks, which is why two of them are from Emerald alone. I have better and more recent memories from this generation which is one other reason as for why I like the music better. My favorites would be these:
Abandoned Ship. A mystery ship stranded in the sea... and a mystery tune to go along with it. Suited it just perfectly.
Battle Frontier. The first time I arrived at the Battle Frontier in Emerald, I was amazed at how large it was. And at that moment, I never thought I would spend hundreds of hours there in the future, winning, losing and obtaining Symbols. The music was always with me, and it truly lives up to the epicness of the place.
Frontier Brain Battle. If the Frontier in itself was awesome, the only thing that could compare was when you battled the Frontier Brains. To get a Symbol, to get more BP, or in the worst case, lose and come back later. With great music to go along with it.
Colosseum & XD
Only side games I have played, and they have some awesome music. Obviously higher quality compared to the handheld games at the time, and wonderful melodies to go along with it. I have several favorites, the ones I like the most are the following, three or two depending on how you count.
These games had several interesting characters. Miror B. is one of them, and he had some awesome music. I like his music in both games, even if they are completely different.
His theme in Colosseum was different from anything I had expected from the series at that point, and
his theme in XD was different from the Colosseum theme but still awesome.
The third one to get my vote here is the
Colosseum Credits, an epic piece and one of the best credits tracks in the series. I love it when they make the credits music as epic as possible and this game was one of the best at doing this, another game pair also did it incredibly well but more about that a bit below.
FR/LG
First pair of remakes, I think they did well at remaking the music but they didn't add that many new tracks which is a bit sad. What they did do, they at least did well. To me, the best ones are:
Vermilion City - Mainly for the same reasons as the original, very well remade. Still powerful and still energetic which was all it needed.
Sevault Canyon (and some other areas on the Sevii Islands, don't remember exactly which) - Another remake, but from G/S/C rather than R/B/Y? This is the same theme that plays at Lake of Rage and the surrounding routes. And it is really well done, I actually like this version better than both the original and the second remake in HG/SS.
Credits - As said, FR/LG didn't add much new music, but this was one of them... kind of. The more people who worked on the game, the longer credits. And longer credits means longer credits music. They expanded and improved on the original really well. Not my favorite credits music from the series, but definitely one of the best tracks from these games.
D/P/P
A really great soundtrack this time around. What should I say more? I don't know. Oh yeah, like with Emerald being my favorite from R/S/E, Platinum is my favorite of these three and had some super awesome exclusive music that D/P missed. Best ones:
Sunyshore City. Wonderful track that suits the city perfectly. I was blown away the first time I entered Sunyshore in Pearl and heard this. Really powerful with a bittersweet hint, combining two things I love and making it wonderful.
Giratina Battle Theme. Fantastic theme suiting a great legendary. More importantly, the volume of this really impressed me, I didn't think it was possible to do something this powerful on a DS. Great melody with lots of variation without ever losing the power, love it.
Frontier Brain Battle. While I didn't play the Platinum Frontier when it was new as much as I had played the Emerald Frontier earlier, the Frontier Brains had epic music this time around as well. Really made it enjoyable every time I battled them.
HG/SS
Regardless of what I think of these games, I can't get around the fact that they do have some great music. And they added lots of new music too, unlike FR/LG. As well as remade several tracks from R/B/Y/FR/LG that wasn't in GSC. In fact, my favorites this time around are mostly the newer tracks and the missing remade ones, even if my choices doesn't mirror that completely
Ho-Oh Battle Theme. Another wonderful legendary theme, well done in every aspect and suits the situation well even if I felt the story was rather forced. At least the music was great.
Ecruteak City. Of the two versions of this, I prefer this over Cianwood. It took care of the melody better and made it feel like it was going somewhere while the Cianwood version wasn't as moving to me.
Cinnabar Island. Out of all the missing Kanto songs from G/S/C, this was the one that to me, was remade in the best possible way ever. It was perfect for a damaged and destroyed Island, the melody was the same as in the core Kanto games but slowed down and done with different instruments. Just awesome. Like with Goldenrod City in G/S/C, I often found myself going to Cinnabar Island in HG/SS just to hear the music. Which isn't a compliment seeing how little enjoyment I got out of these games otherwise, but for what it was worth, this track was at least great.
B/W
One of my favorite soundtracks in the series, and I can only pick three songs? Tough. I'll do it though. Everything stood out in some way, but some more than others.
Entralink. Quite odd to make such an epic track for a place where you pick up Pokemon and Items from the Dream World and connect to other games. Nonetheless, it was great. Loved it.
Emotion (also called Unwavering Emotions or An Unwavering Heart, the most loved child has the most names, am I right?) This really lived up to its name. It brings forward emotions. And since I have the most emotions for this generation... this is one of the most special tracks to me, and one of my favorites. I have mentioned that I like bittersweet/melancholic ("sad") music, and this is... perfect in every aspect. I got a whole rush of emotions when I heard this again in X/Y.
Black/White Credits. I mentioned in Colosseum that there was another game pair that did the credits music just really well... and this is it. Just epic. Even better, it was en epic way to end an epic game. Or start it, since the post-game was something I wouldn't have wanted to miss. I don't think the series will ever be able to top this when it comes to credits music.
B2/W2
Another of my favorite soundtracks obviously, adding even more goodness to what B/W already had. Losing some of the songs from the original pair wasn't a problem since there was more than enough new awesome ones to make up for it.
Iris Battle Theme. The most interesting trainer battle theme to me, very varied and at points weird. But in a good way. I'm also biased since she is my favorite Champion.
Black Tower. This was odd as I didn't care much about it first, but it grew on me. Never really expected to hear contemporary music in a Pokemon game, so that was a great surprise. It never really got tiresome either, I still love it even after beating those 1000 trainers in Unova's Challenge. Wish I could go back again, will see what the future brings...
Aspertia City. This is also rather strange since I'm not sure if I like the music or if it just has so many good memories attached to it. A simple and sweet melody for my favorite starting city, carrying both happy and sad tunes which I appreciate.
X/Y
Yet another great soundtrack, albeit not as memorable as the one from last generation... yet. Several good songs though.
Professor Sycamore's Theme. There has been many great character themes in the series, and this is one of my favorites. I love the instrumentation and the melody.
Laverre City. Good theme for a great city, varied enough with a great melody and instruments.
Pokémon League. A wonderful final theme for the final frontier of the game... or something like that. Probably my favorite of all Pokemon League Themes from the series. Makes me want to return there even if I'm not going to battle the E4 again.