Scolipede, Cinccino, Samurott, Whimsicott, Haxorus, and Chandelure are some of my favorites from this gen. <3
Hydreigon is really cool also, but it's a pain in the butt to get. Same with Volcarona, although I just caught mine, raising Larvesta all the way to level 59 sounds like an awful time.
Scolipede is seriously awesome. He outruns stuff, hits nice and hard, and can take some physical hits. It's also really easy to get. .3.
Well, a time-traveling phone booth can only take you so far...