^^^ That is actually fairly cool in terms of breaking Blissey down.
Now I'm sure lead Empoleon has been popping around a lot in the past...but I have found this one has been very effective:
Empoleon @ Shucca Berry/Focus Sash/Chople Berry
Torrent
52 Def/104 Atk/100 Spd/252 SpA
Rash
-Stealth Rock
-Surf
-Aqua Jet
-Grass Knot
Pretty cool lead IMO, as it handles most of today's leads and more very well.
Unfortunately it has to be either Rash or Quiet. Rash+100 Spd EVs hits 181 Spd, which is usually enough to outspeed many pokemon, like Metagrosss, Machamp, Tyranitar, etc. However, if you don't mind being slower, you can move the 100 Spd EVs to HP/Def and go with Quiet so that your SpD doesn't drop. Def is too important to drop, as Empy needs to handle some EQs and big fighting attacks.
Here are the top 10:
Metagross: The only one that really can cause trouble. I used to think SR+MM+BP+Explosion ones still existed, but apparently not. They all have EQ+BP these days, so you lose. At least you can get SR up. But if they lack EQ, you can Surf for a 2hko some of the time. You always survive the 1st EQ. You can run Shucca if you want to win though.
Azelf: Surf+Aqua Jet=KO with these EVs against Naive Azelf. Easy to get rid of. If it taunts or attacks, no rocks. Usually it gets those rocks but at least you kill it and can get your rocks up later, since you can usually survive anything.
Jirachi: 2hko with Surf, can set up rocks, doesn't mind the Trick too much. Can handle any attack Jirachi throws at you too, which is very nice.
Swampert: Grass Knot will KO 252 HP/0 SpD 60% of the time, meanwhile Swampert needs to invest a fairly significant amount of Atk EVs in order to KO you with its EQ. With Shucca, you will always win.
Aerodactyl: Easy as hell, Surf+Aqua.
Hippowdon: Surf hurts him very badly, doing 85% minimum and capable of KOing (though only 2%). However, he cannot KO you back either, so you SR, then Surf. If he chooses to kill you, it is likely he isn't going get rocks up for a bit of time. Shucca can help if you don't want to lose too much HP, but you still get KOed after 2 Earthquakes
Tyranitar: Surf will deal quite some pain, however a CB EQ is going to hurt a lot. Quite a lot. Using Shucca however, can save you and if you can outspeed, you win.
Other leads: If you use Chople, you can beat those Infernape leads. Heatran is KOed by Surf if it is Naive. You basically beat Bronzong, as you can set up your rocks then Surf it a bit. Eventually, he will EQ you to Torrent and your Surf can finish him off.
Like most slow leads you will lose to any leads that try and sleep you, like Breloom and Roserade.
Concerning the item: I like Shucca a lot, since EQ is a very common attack and it can help cushion any surprises. However, you can usually survive most EQs anyway, and its those fighting attacks that hurt considerably more. Those Close Combat's are almost always going to put you into Torrent range after Chople, which will often net you a free kill thanks to the power of a Torrent boosted surf.
Sash is a nice mix inbetween. Of course, it doesn't work late game, and Empoleon is not perfect at preventing rocks, he just wins.
Hydro Pump can be used, and it would allow you to always 2hko metagross (and deal a crap load of damage off of a Torrent attack), and it would let you move EVs out of attack into HP/Def. However, its accuracy is quite shaky, as 2 Hydro Pumps hitting is about the same as 2hkoing Metagross with Surf. Still, it could be handy I suppose, if you are feeling a bit lucky. With Hydro Pump, you can stuff 156 EVs into Def, and you can beat Infernape most of the time now. As long as pump hits though.
Overall, I've found this Empy to be extremely awesome but I'm still experimenting.