I like playing games together, so my highest priority is a very cooperatively inclined atmosphere in regards to tactical combat and player interaction. I also enjoy fairly strict rules enforcement, or at least clearly defined changes before it becomes relevant. As far as setting goes, I prefer action centric situations rather than situational role-playing exchanges.
While familiar with older editions, I've only actually played D&D 4E and like it just fine. I have a full time job and other hobbies so I can only play once or twice a week depending.