If I were to play a RTS game again, it would no doubt be SC2 but I can't handle the stress anymore. RTS takes the most skill of any genre of games. I was stuck between destroying noobs and getting destroyed by pros. Zerg all day long.
Started on the campaign last night, and I found it pretty enjoyable. I like how they let you choose how to evolve your swarm and actually play the role of the Zerg leader.