I found sites like Monster and Hotjobs to be pretty much worthless. The job openings are often outdated and you won't hear back from most people at all. Also, the majority of the jobs on those sites where the people WILL contact you are for things like outside sales. If you see something that says it's "Marketing", expect it to be basically going from business to business (uninvited) and trying to sell them stuff. I don't know about you, but that doesn't sound like fun to me.
Some people may have had luck with those sites, but I definately don't recommend them. I personally found more luck in the classifieds section of the newspaper.
Also, like someone said before, networking is probably the best thing you can do. Alot of people I know who have good jobs found them through talking to people.
Good luck with your search! Oh, and wish me luck too cause I'm about to start looking again.