Most of my campaigns are a pretty good mix of roleplay and combat. I don't plan my games in too great of detail in advance and prefer to shape the world/campaign around the characters. So "jumping the tracks" isn't much of a problem. I am especially looking for players that like to try interesting things and know how to play their characters. If you tend to come up with interesting/unorthodox things during a game I will usually reward it in some way.
I haven't run/played too many games outside D&D 3.5 since my usual group was never too interested in other ones. Though I have always been open to trying new things. I used to play 2-3 games a week when I was in college but work and moving has proven a pain in that area. My games and characters are usually light-hearted with some serious moments thrown in.