I'll be honest, I picked Black 2 because I have a weird sense of loyalty after picking Black 1.
Anyway, just go here to find out what pokemon are exclusive to what game, and you can also check other "exclusive"-comparisons from the menu on the right =)
And DON'T tell me what Electric Pokemon White 2 got. I'm already pissed about having to choose between favourites, and I don't need 'DAMN White 2 has THAT one?'-thoughts. ;P
Edit: Mwahahahaha I checked because I hate life. No jealousy, and I got the game with the coolest bugs!