Suggestions for a vacuum?

Here's the deal, I am a college student moving in to a new place in the fall and hopefully will be adopting a dog not to long after. I am in the process of furnishing the place, so as you can imagine, I'm getting a lot of freebees from relatives and people throwing stuff out so I don't have to spend a lot of money. The one thing, however, I feel like I can't be cheap about is a vacuum. What I am looking for are suggestions for which vacuum I should get considering I am getting a dog? I've done a little bit of research and everyone swears by the Dyson Animal but at $500+ I was hoping for other suggestions. I am also thinking of getting a carpet rake just to take a little pressure off the vacuum. So any suggestions?