Hmmm...Mac or PC

I have a 24" iMac with 4Gb it’s awesome but I would like to have another screen. Hopefully next spring I will have one. I like dual screens more than working on one. The only thing that bothers me is that when each program is launched it is expanded to the size of the screen and when multi tasking it becomes a PITA. I could use the “spaces” feature, but I personally don’t like it that much.