I just bought StarCraft 2 for $20 since it was on sale. I tried the demo, I didn't like it too much, but you can't beat the price and it was only on sale for a short time.
I haven't enjoyed Warcraft 3 in a very long time, I think I am just burned out.
Diablo 3 is fantastic based on the demo, but I will wait for the ps3 release because d3 sometimes lags on my new computer.