Instead of picking a specific Pokemon, I will pick two types that I found to be excellent in gen 5. These are the Dragon and Bug types most notably Haxorus and Volcarona both of which I had trained and fully evolved by the 7 gym(I will admit that was painful due to the new leveling system but was well worth it even EV trained them like I do to any Pokemon I use(so many basculin, litwick, elygem, heredier, and whatever the evolved form of patratt is called again...).