I'm playing Nasus until I have enough for Iorek...I mean Volibear.
Regarding Nasus...His Q is potentially the most powerful move in the game. If sufficiently fed, he can ONE-SHOT ANYTHING. That will never happen, of course, but the potential is there. Your Q should be at least +150 by the time your team is assaulting the enemy, the more the better. How do you get there? By taking Q first, and last hitting minions with it from the very start. Extra gold from Spirit Fire is nice, but having extra power on Siphoning Strike earlier will turn a losing game around.
Pic related. WinAnyways.PNG (772.49 KiB) Viewed 860 times
I'm also rather partial to Kayle, she was the first champ I bought. I don't use her as much, though, since I don't have so solid an idea for her build.