I hated Light... He had no meanings behind his motives. He said he wanted to rid the world of criminals, but it just made him a criminal because he killed innocent people. With Lelouch he was trying to win back the independence on Japan. Britannia just killed people for no reason and Lelouch saw it wasn't fair so he rebelled. I don't see anything wrong with his motives even if he does sometimes handle things in a harsh way... In the end it's for a good cause.
I have to say Lelouch because he succeeded in his plan to make the world a better lace. Light failed.
I'd have to say Light, since I haven't seen the anime the other guy is from. Plus I love his laugh in the last episode.