One thing I noticed when I went back to one of my old Gameboy games was that your starter Pokemon was your ace in the hole. Your one Pokemon that could save the rest of your team and in some cases single handedly take out the Elite Four. I wanted to make a team of these In-Game-Beasts and try and bring out their strengh in competitive battling. Initially I wanted to make it an OU team, but noticing that only 3 out of my 12 choices was actually OU I decided for a good solid UU team.
"HellFire" Typhlosion @ Choice Scarf
Nature: Timid
Ability: Blaze
EVs: 252 Spe, 252 SpA, 4 Def
-Eruption
-Flamethrower
-Focus Blast
-HP Electric
All I can say about this is AWESOME. The choice Scarf lets it destroy all the Roserade and Yanmega leads running around. Eruption has massive power that can be used to sweep until something with Flash Fire comes out, in which case I just switch to Blastoise as none of those Pokemon can KO him. HP Electric and Focus Blast don't really see much use, but they're there to help with coverage if I need to bring him out later on in the match, or if he loses his scarf via Knock off/ Trick.
"Crush" Blastoise @ Leftovers
Nature: Bold
Ability: Torrent
EVs: 252 HP, 252 Def, 4 SpA
-Surf
-Yawn
-Ice Beam
-Rapid Spin
Blastoise is my token spinner, and overall tank. He can take powerful hits from a wide range of types and still phaze out the other teams sweeper with Yawn. Toxic has been replaced with Ice Beam to help with Roserade problems and because Venusaur is better suited to ToxiStalling. I switch him in when Typhlosion sets off Flash Fire and get a KO, usually at the cost of a good deal of HP however. Note that even after a Nasty Plot Houndoom and Ninetales can't OHKO him with HP Electric or Energy Ball respectively, while he OHKOs with Surf.
"FatherEarth" Torterra @ Yache Berry
Nature: Adamant
Ability: Overgrow
EVs: 252 HP, 252 Att, 4 Def
-Stealth Rock
-Crunch
-Earthquake
-Superpower
Torterra is often given a bad rep, as the other two 4th gen starters were deemed worthy of the OU tier and he was not. Still, he does his job on this team well. He sets up Stealth Rock and usually gets some KO's. Earthquake is for good reliable STAB, Superpower is there in case something like Facade Clefable gets going after Blaziken is down, and Crunch is to hit the Ghosts that EQ and SuperPower miss. He has decent tanking ability, taking Physical hits pretty well and doing some major damage in the process.
"GameCock" Blaziken @ Liechi Berry
Nature: Jolly
Ability: Blaze
EVs: 252 Spe, 252 Att, 4 Def
-Agility
-Blaze Kick
-Earthquake
-SuperPower
Blaziken is my mid game sweeper, his main goal is to draw out any scarfed pokemon or those with priority moves for my other Pokemon to handle. He has netted a few good sweeps for me so far and I expect a decent percentage of matches ending with this guy sweeping the other team. The moves provide pretty good coverage, though Stone Edge would provide for even better I just can't get over the horrible accuracy. Superpowers stat drops I don't really mind, especially with the Liechi Berry there to take away one of those attack losses.
"Dundee" Feraligatr @ Salac Berry
Nature: Adamant
Ability: Torrent
EVs: 252 Spe, 252 Att, 4 HP
-Waterfall
-Return
-Substitute
-Swords Dance
SD Feraligatr, plays kinda like SubPetaya Empoleon does in OU. Sub and SD up until berry and Torrent activate and pull off a sweep. It's 6-0ed a couple of teams since I started testing it, so needless to say I'm gonna keep it. Return and Waterfall provide enough coverage to KO alot of the UU metagame, only being stopped by walls like Milotic (I just can't get around it can I).
"Monster" Venusaur @ Light Clay
Ability: Overgrow
Nature: Calm
EVs: 252 HP, 252 SpD, 4 SpA
-Light Screen
-Toxic
-Grass Knot
-Synthesis
Venusaur has taken the place of my SubSeedSceptile to act as a special wall and to absorb Toxic Spikes. His main purpose is to stop Milotic, who after testing proved to be a major problem for my team. Light Screen not only helps him easily take Milotics Ice Beams but it helps my other Pokemon switch in on another Poke who has been giving me major problems, Roserade, who can only really be revenge killed. Venusaur was chosen over Meganium for one reason, his Posion type. This makes Roserades Sludge Bomb only a neutral hit, and allows him to absorb Toxic Spikes, which Blastoise really doesn't like having to spin away. Also gives me a useful Fighting resist.
All Sprites courtesy of Arkeis.com

"HellFire" Typhlosion @ Choice Scarf
Nature: Timid
Ability: Blaze
EVs: 252 Spe, 252 SpA, 4 Def
-Eruption
-Flamethrower
-Focus Blast
-HP Electric
All I can say about this is AWESOME. The choice Scarf lets it destroy all the Roserade and Yanmega leads running around. Eruption has massive power that can be used to sweep until something with Flash Fire comes out, in which case I just switch to Blastoise as none of those Pokemon can KO him. HP Electric and Focus Blast don't really see much use, but they're there to help with coverage if I need to bring him out later on in the match, or if he loses his scarf via Knock off/ Trick.

"Crush" Blastoise @ Leftovers
Nature: Bold
Ability: Torrent
EVs: 252 HP, 252 Def, 4 SpA
-Surf
-Yawn
-Ice Beam
-Rapid Spin
Blastoise is my token spinner, and overall tank. He can take powerful hits from a wide range of types and still phaze out the other teams sweeper with Yawn. Toxic has been replaced with Ice Beam to help with Roserade problems and because Venusaur is better suited to ToxiStalling. I switch him in when Typhlosion sets off Flash Fire and get a KO, usually at the cost of a good deal of HP however. Note that even after a Nasty Plot Houndoom and Ninetales can't OHKO him with HP Electric or Energy Ball respectively, while he OHKOs with Surf.

"FatherEarth" Torterra @ Yache Berry
Nature: Adamant
Ability: Overgrow
EVs: 252 HP, 252 Att, 4 Def
-Stealth Rock
-Crunch
-Earthquake
-Superpower
Torterra is often given a bad rep, as the other two 4th gen starters were deemed worthy of the OU tier and he was not. Still, he does his job on this team well. He sets up Stealth Rock and usually gets some KO's. Earthquake is for good reliable STAB, Superpower is there in case something like Facade Clefable gets going after Blaziken is down, and Crunch is to hit the Ghosts that EQ and SuperPower miss. He has decent tanking ability, taking Physical hits pretty well and doing some major damage in the process.

"GameCock" Blaziken @ Liechi Berry
Nature: Jolly
Ability: Blaze
EVs: 252 Spe, 252 Att, 4 Def
-Agility
-Blaze Kick
-Earthquake
-SuperPower
Blaziken is my mid game sweeper, his main goal is to draw out any scarfed pokemon or those with priority moves for my other Pokemon to handle. He has netted a few good sweeps for me so far and I expect a decent percentage of matches ending with this guy sweeping the other team. The moves provide pretty good coverage, though Stone Edge would provide for even better I just can't get over the horrible accuracy. Superpowers stat drops I don't really mind, especially with the Liechi Berry there to take away one of those attack losses.

"Dundee" Feraligatr @ Salac Berry
Nature: Adamant
Ability: Torrent
EVs: 252 Spe, 252 Att, 4 HP
-Waterfall
-Return
-Substitute
-Swords Dance
SD Feraligatr, plays kinda like SubPetaya Empoleon does in OU. Sub and SD up until berry and Torrent activate and pull off a sweep. It's 6-0ed a couple of teams since I started testing it, so needless to say I'm gonna keep it. Return and Waterfall provide enough coverage to KO alot of the UU metagame, only being stopped by walls like Milotic (I just can't get around it can I).

"Monster" Venusaur @ Light Clay
Ability: Overgrow
Nature: Calm
EVs: 252 HP, 252 SpD, 4 SpA
-Light Screen
-Toxic
-Grass Knot
-Synthesis
Venusaur has taken the place of my SubSeedSceptile to act as a special wall and to absorb Toxic Spikes. His main purpose is to stop Milotic, who after testing proved to be a major problem for my team. Light Screen not only helps him easily take Milotics Ice Beams but it helps my other Pokemon switch in on another Poke who has been giving me major problems, Roserade, who can only really be revenge killed. Venusaur was chosen over Meganium for one reason, his Posion type. This makes Roserades Sludge Bomb only a neutral hit, and allows him to absorb Toxic Spikes, which Blastoise really doesn't like having to spin away. Also gives me a useful Fighting resist.
All Sprites courtesy of Arkeis.com