Any of the Total War games, but I think you may wanna leave them a bit till you're more comfortable with RTS games, as they are quite complicated.
Company of Heroes is great. Simple but dramatic WW2 game play, with Americans and Germans, and British if you get the expansion. Some really cool game play features; you don't have to gather berries and chop wood like in AoE, you fight for control of map regions which give you resources.
Same applies to Dawn of War I and II(based on games workshop's Warhammer 40,000) as they are made by the same developers, but are different enough to retain their awesomeness.
World in Conflict is another good one, easy to get to grips with, no resources or base building to worry about, just combat and tactics
Have fun!