I just bought a Dell Inspiron 6000 on ebay and love it...no complaints at all. If anything, it's a bit heavy, but has a nice big screen and is fast. I don't use it for games, though. I came with 2G RAM, 1.6GHz CPU and 80G Hard drive. I got it for $157 used, plus shipping.
I personally don't like HP since they merged with Compaq, and I've never had a good experience with Compaq. I actually went to a forum where they got professionals' opinions on computers, and they were promoting Compaq, but we weren't told that. Once we found out, over half the people invited were asked to leave because we had nothing but negative things to say about Compaq.
But, again, that's just my personal experience.