im a big fan of Objective scenarios, not the 1Hr game types,
Like a whole day game, but at certain times certain things earn you extra points.. like captruring a certain base.
Special factions are good too.. its nice when victory (or defeat) is snached away from you due to the appearence of a special faction..
(kind of like Staargate 2005.. Awesome game..)
Also, Anything slightly Urban..