I am planning to buy xp pro sp3, because I want to build a reliable, slimmed down system for under $450. I only need to do documents and some software writing. If I get Vista I have to go 4G or more, and $600 plus for hardware, and I don't need that much power.
My only concern, besides its vulnerability, is that it will no longer be compatible with newer software such as microsoft visual studio 2009 or asp.net 2008. Will that be an issue, since ms doesn't care about xp anymore?