1) Braviary
I love birds of prey, and Braviary is one of my favourite Pokémon of all time. His design is awesome, and he's not bad in battle either. It's just a shame that Defiant doesn't kick in when you use Superpower — Braviary would be deadly. Oh, and I love his shiny form. I want one.
2) Stoutland
When I first played Pokémon White, I kept my Lillipup in my party for the whole game. I thought Lillipup was adorable, and Herdier looked pretty cool — and when she evolved again, my first thought was how much her Pokédex entry reminded me of my own dogs. The Big-Hearted Pokémon? Rescues people from water? Big and shaggy? Stoutland is like a cross between a St Bernard and a Newfoundland, and I love it for it.
3) Sigilyph
Whenever I play through a Pokémon game, there are a few Pokémon types I always have on my team, one of them being a Flying-type. By the time I got to Nimbasa City on White, I still hadn't found a Flying-type that I wanted to use. That was, until I battled N at the Ferris Wheel and faced his Sigilyph. It looked weird, for sure, but it was surprisingly resilient, and I decided that it might be a good addition to my team. I was lucky enough that the one I found at the Desert Resort had a modest nature and the ability Magic Guard, and she did a fantastic job through the whole game. Such a good job, in fact, that I ended up using Sigilyph again in Black 2 — N's, in fact, bringing things full circle. Funny how these things work out.
4) Dwebble and Crustle
Speaking of Black 2, a surprise encounter led me to a Pokémon I might not have used otherwise. While grinding for Elesa on Route 4, I decided to head to the Desert Resort. "That'll work," I thought. "Zuzu [my Azumarill] will like it there, with the Ground- and Fire-types; maybe I'll find N's Darumaka this time. Oh, here's a Pokémon now, maybe this is— no, it's a Dwebble... Wait." Out of nowhere, I'd found a shiny Dwebble; I named him Malach, and he immediately joined my team.
Malach quickly became one of my favourite team members, and thus Crustle one of my favourite Pokémon. He was the linchpin of my strategy for fighting Ghetsis, laying down Stealth Rock right off the bat. I really should transfer him up to Gen VI...
5) Tepig, Pignite and Emboar
Finally, we have the Tepig line. I have to admit, another Fire/Fighting type starter line annoyed me a little, but using Emboar throughout my playthrough of White was nothing short of awesome. Firstly, Tepig is completely adorable; secondly, my Emboar was the reason I was able to defeat Ghetsis. That Hydreigon of his took out four members of my team — Simisage, Zekrom, Sigilyph and Samurott — and only didn't knock out Stoutland because I refused to send her in against it. Emboar somehow withstood a Surf with half his HP left, and then smashed the nasty dragon with Brick Break before stomping Ghetsis's Bisharp and Eelektross. Without Emboar, I probably would have lost that battle. Recently I bred a competitive Tepig, and I named him Emmett, after my Emboar from White.