Looking for a good RTS for about 20 bucks.

So far I was thinking Company of Heroes or Rome: Total War, and It's expansion. I need alot of play time and replay value, and I also need a game that can support widescreen. I know those ones can, what else is there I could get for around 20 or 30 bucks that I am missing out on?

My RTS collection sucks, the only rules are 20-30 bucks and widescreen support. If it needs an INI tweak thats just fine. I would prefer newish games around 2004 and up.