I would stick with XP 32 bit on my main rig, because it is test and proven, and has the best driver support. Like Vista, Windows 7 offers no great improvements. If you want to increase your RAM, go to 4GB with 32 bit and see if there is any improvement for your application. I went looking for Vista driver for my Linksys wireless adapters, and found no Vista drivers (32 and 64 bit) available, even for current products. There are no wireless adapters on this list.
http://www-ca.linksys.com/servlet/Sa...=8871512855B02
I would have expected more from a reputable company like Linksys/Cisco.
I also found some bugs in Windows 7, but what do you expect, they told me it was Beta. I play with Windows 7 on a fourth computer I have. It has an SIS chipset on it, and when I installed it, the onboard network and sound did not work. I got the sound to work, but I doubt if I will ever get the LAN to work.
I didn't like the start menu in Windows 7 (and Vista), and I noticed that there was no option to revert back to "Classic".
I think the only real reason to upgrade from XP is for a change in scenery. You can decide how important that is to you.