Funny, but the OP just asked the question that I was about to post on various forums.
I have a Gateway 506GR running Intel Pentium 4, 3.40 GHz. It has dual DVD-Rs and is running XP sp3. The biggest problems for me (and that is slowing the PC down) is a 320 gig hard drive that is almost full. Also, I also play flash games from the internet and now find that I really need to add more RAM and maybe a new video card.
So I'm planning to install a larger HD (along with an XP re-install) and then add the rest of the stuff that's on my old HD. Adding an additional 1 gig of RAM to bring it up to 2 gigs, which is plenty for the type of games I play (I checked with the gaming website's tech support). Also considering adding a better video card. That took a bit of searching but I did find one online. Total upgrade price: approx. $215
I'm an XP fan and am not worried about support that much. One of our tech guys said that most of the bugs have been worked out of it by anyway. The last survey I've seen showed that 43% of home users are still staying with XP. It must be doing something right!