God, this is like the opposite of Sophie's Choice. Put them all in the gas chamber, for all I care...
If I had to choose one, it'd probably be Serperior. I used Samurott when playing through Black and ended up kinda hating it for its 'meh' movepool, stats and design. It was just mediocrity incarnate. Emboar, on the other hand, is a critter than I should like but really, really, don't. I mean... just look at it! It's so ugly and slow, and Fire/Fighting types have been done to death. So, that leaves Serperior. It looks sort of OK, and it's really fast, but it is a Grass-type, so that's kind of a Debbie Downer...