-The one on the left is obviously the grass starter. Those are leaves on the tail, not a poorly drawn flame. It also looks pretty reptilian-ish. Definitely the most unique-looking of the group. I'm very interested in this one.
-I'm going to guess the middle one is some sort of fire rabbit! Rabbits are cool. Heck it already looks better than the piece of crap that is Chimchar. I'd LOVE to see what the final evolution of a flaming rabbit would look like.
-The one on the right confuses me. I have no idea what it is. Its design also looks a little bland to me compared to the other two. But whatever it is, it's final evolution will indeed be a bad*** like every other starter (unless we have another Meganium).
Overall these are probablly the most complex-looking starters we've had in the Pokemon series. If you look back at the previous starters, they're pretty simple in their design. In example, if we saw silhouettes of all of the other gen starters, we would easily be able to point out that Turtwig is a turtle, Treecko is some sort of gecko, Torchic is a chick, etc.