When I was going through my jobhunt after graduation (a very long one!) people would always always ask me, "Did you try Monster.com?" and I wanted to, "YES AND IT IS USELESS!"
I've had a lot of look with Yahoo HotJobs though, and occasionally careerbuilder.
Since I'm into publishing/media jobs, I like:
And, of course, Playbill.com for NYC theatre jobs.