Easily - Minigore - Jet Car Stunts - Hook Champ - Defender Chronicles - Stair Dismount - Trenches - Battle for Wesnoth (future update) No particular order; And why did you make this a separate thread when you could have put "Best OpentFeint/Plus+ Games."
In addition to the above list - Bird Strike - Starball - Hi, How Are You - Charmed - Battle Bears - Wheeler's Treasure - Steam Wars - Space Invaders Infinity Gene - Karnival - GeoSpark - Skullpogo - Moonlights - 33rd Division - Invisible Links - Arachnadoodle - Ynth - Depict - Must.Eat.Birds - GeoDefense (and Swarm) and omg there's more but these are just the ones off the top of my head!
Super Quickhook actually makes it feel like part of the game with custom notification message things, rather than just being tacked on like so many other games seem to do.