Starcraft. Only just started playing it
Really want to get the second one, but the computer I mainly use for gaming is so old and shitty that it overheats playing SCI...
Luckily I'm getting the Excel AL-570 computer very soon, and it kicks ass (Compared to what I have. Probably isn't that amazing...). Looking forward to getting the second one, it looks like a ton of fun, I watch Husky and Totalbiscuit casting all the time.
And enjoy dawn of war! It's awesome. But really, if you haven't, get the expansions. They make the game so much better.
I used to play it a lot, but now that I've actually tried RTS's like starcraft where there's an opportunity for micro, unlike AoE and DoW that I've been playing for years, I'm really warming to that style. I now dislike squad based RTS, I feel that company of heros would have been 10x better if it wasn't squad based.