There are two sites I used aggressively, Dice.com and Monster.com, and one I used later on that proved to be a valuable resource, Craigslist. Dice is geared specifically toward Technical Positions, however it was my experience that they were higher level positions and weren't looking for recent graduates. Every once in a while I would get a response to a submission I'd make, but I never received a cold call from recruiters scouring Dice. With Monster, however, I received many cold calls from recruiters, and overall the jobs tended to be a better fit for where I was in my career.
Later on in my search someone suggested I use Craigslist. I was suspicious of this at first, but I actually had some very good opportunities arise from it. I uploaded a resume to each city I thought I'd like to live in, removed all sensitive information, and within a few days I was receiving emails from potential employers. Some were worthwhile, and some not so much, but regardless I think it's a powerful tool I could have made more use of.