-insert comment about this thread being done before here-
Anyway,here are my choices...
Fire:
Arcanine 
I friggin' love this thing.It looks plain awesome.That,combined with its overall good battling ability,and you have my favorite Fire-type.
Grass:
Venusaur 
If I ever want to use a Grass-type,Venusaur is usually the first one to come to mind. Its deceivingly sturdy when you need it to be,and still packs a decent punch in return. Access to Sleep Powder and,though I use it less,Stun Spore, also help it in battle. Plus...its a giant dinosaur-frog-plant-thing. You don't often get much better than that.
Water:
Starmie 
There is no better offensive user of Rapid Spin than Starmie. With an impressive set of moves,incredible Speed and strength,pseudo-immunity to Status,and reliable recovery,Starmie has no peer. If I ever have a team with Hazard-weak Pokemon,I pick Starmie to clear the field. Not only that,but knocking your opponent around with a freaking starfish is really good fun.
Electric:
Manectric 
Manectric looks incredible,and has the prowess in battle to back it up. It has a somewhat unique movepool for an Electric-type,sporting attacks like Switcheroo and Flamethrower,which allow Manectric to get past Pokemon its Electric brethren cannot. Having an ability that boosts its attack power in Lightningrod also helps Manectric's offense,which makes it a good partner for a Water- or Flying-type.
Ice:
Glaceon 
I.Love.Glaceon. It is elegant in appearance,but this dog has a very painful bite! Glaceon has saved me from defeat on numerous occasions, which has quickly earned it my respect. It takes hits surprisingly well,and hits back incredibly hard. Combining it with Hail makes it even more menacing,since it gains precision Blizzards to smack the opposition with. It doesn't have many other offensive options,but if I'm using my Hail team,and a Blizzard revenge-kill isn't the best option,I use another member of the team.
Dragon:
Salamence 
A giant blue and red dragon that can either rip you to shreds or shoot beams of fire and water at you. Yeah...You just don't mess with Salamence. It works like a Dragon-type Arcanine on steroids,with decent bulk and impressive offenses on both ends. If I want an offensive powerhouse to rip through my opponent,I use Salamence. If I want a surprise wall to troll my opponent,I use Salamence. If I want a Special-attacking Dragon-type that isn't Scizor food,I use Salamence. Overall...I like Salamence.
Psychic:
Gardevoir 
Elegant both on and off the field,Gardevoir is a unique Pokemon in many ways. It has the rare ability Trace,which copies the opponent's ability,along with some interesting supportive moves. It also hits like a bus if you go down the path of pure offense. If Pokemon that are ability-reliant get in your way,or if you just want to add some class to your team,Gardevoir is an excellent choice.
Ghost:
Banette 
Picking just one Ghost was rather hard,but in the end I decided on Banette. What? You don't know what a Banette is? Well,it is without a doubt the most lulzy Trick Room lead there is. It can battle literally any Pokemon and take it down,at the cost of its own life,thanks to Destiny Bond.Using said move right after a Trick Room is such fun times,since literally nobody knows what to expect from the Marionette Pokemon. Also,it looks just plain awesome.
Bug:
Scizor 
One of the coolest-looking Bugs there is. You just don't mess around with a red robo-mantis with face claws. Everyone knows everything there is to know about Scizor,so there isn't much I can add. It makes the other Bug-types feel bad about themselves,which,while that is no difficult feat,is something worth mentioning.
Flying:
Swellow 
Underestimate Swellow and suffer the consequences. With over 400 Attack with Guts activated, any unresisted attack from this bullet train of a Pokemon will leave the opposition gasping for air while you ready your next assault. While Swellow won't typically last long enough to sweep teams on its own,the momentum it can gain allows the rest of the team to go for the win.
Poison:
Nidoking 
All hail the King! My all-time favorite Pokemon,Nidoking,just by appearance,is on a level all his own. On the battlefield, he proves he deserves the title of 'King'. In the 4th Generation,Nidoking was an impressive physical attacker with moves like Earthquake,Head Smash,Megahorn,and the Elemental Punches.It also worked well as a potent mixed wallbreaker thanks to its access to moves like Thunderbolt and Ice Beam. In Gen 5,Nidoking received a gift from above. That gift was Sheer Force,an ability that boosts every attack that has a secondary effect,in exchange for that effect being negated. Nidoking has a multitude of moves that abuse that ability,including Earth Power,Sludge Bomb,and the aforementioned BoltBeam combo,as well as Flamethrower to roast whatever the other moves can't harm. Whenever the opportunity presents itself,I give the King time to shine in battle.
Fighting:
Hariyama 
An impressive-looking Pokemon,no doubt. But does it back up that appearance in battle? You bet it does! If trained properly,Hariyama can take a surprising amount of punishment and hit back impressively hard. While Guts can turn it into a potent attacker,what really sets Hariyama apart is Thick Fat,which gives it resistances to Fire and Ice-type attacks. This,combined with Hariyama's impressive defenses,make it a very powerful defender should you want to try something different.
Normal:
Raticate 
Your eyes do not deceive you,that is a Raticate on your computer screen. It might not look horrifyingly intimidating,but for an early-on Normal-type it more than gets the job done. Its surprisingly decent stats and Guts are also bonuses. If I ever feel the need to use a Normal-type,I will take great joy in confusing my opponents with Raticate.
Rock:
Golem 
This was a hard decision,but in the end I chose Golem. It is an awesome looking Pokemon,despite its incredibly simple design. It can also do a variety of things with just one set of moves. With access to Stealth Rock,Explosion,EdgeQuake,and the elemental Punches, Golem is rarely short of options. If you're feeling lucky,Sucker Punch is also an option. I always have fun when I use Golem,and that's what matters in Pokemon.

Ground:
Marowak 
Marowak sets a good example by wearing a helmet.When it's around,your opponents would be wise to do the same.Under Trick Room,Marowak
will kill three or more of your opponent's Pokemon if they don't kill it quickly. EdgeQuake,the Elemental Punches,and Rock Head Double-Edge give Marowak a plethora of options. With the Thick Club item,Marowak's Attack stat doubles,giving it the highest Attack score in the game.
Steel:
Steelix 
A giant snake made entirely out of twisted metal. What isn't there to love about that? You'd be surprised just how much damage Steelix can do,even with his rather meh Attack power. With Sturdy,when combined with Stealth Rock and a Custap Berry,make Steelix an impressive lead. It can set up the Rocks,and attack until it gets down to its Berry,where it can simply go boom to take out its opponent,which will leave your opponent at an early disadvantage.
Dark:
Sableye 
Ah,Sableye.I thought it was the coolest looking Pokemon in Hoenn when I first saw it. Its abilities in battle weren't much to speak of until Gen 5,where it gained the Prankster ability. this ability gave priority to non-offensive moves,such as Will-O-Wisp,Taunt,and Recover. Sableye learns all of these and more. When trained properly,Sableye can take quite a beating. It can cripple physical attackers,walls,set-up sweepers,and even other Sableye if it's fast enough.