Mid: LeBlanc, just a really good hit and run character, her dps early game is just ridiculous. sort of falls behind later though.
Solo top, I managed to do very well with Urgot up there, only thing he takes a bit of practice to get good with.
Support: This is my favorite role so I have every champion for this role, it all depends on who you want to support. but my personal favorite is Zilean, his ult is just game changing if used on the right ally.
AD carry: an AD Twisted Fate is awesome if you can nail the stun card timing.
Tank: I love a good Tanky built Taric. all of his utility from his support spells, while taking really low physical damage due to his W ability, so you really only need to build resistance to be good.
Jungler: Udyr also, easy to use. really balanced, and great at ganks.