-Bluefrog
Um. I'm new to this forum, not new to computers. If you ever get a job working on other people's computers you will notice that people still running XP are more likely to have malware on them than people running Vista or 7. I didn't say Vista isn't bloated compared to XP. I have XP running on a P2 266mhz 128mb RAM thinkpad, and it runs great.
The real problem is that Microsoft has this pattern of obsoleting technology that is still mostly viable. You get into all kinds of driver and compatibility problems when you try mixing older PCs with new Microsoft operating systems, and newer PCs mixing with older Microsoft operating systems. My rule of thumb is use the license that came with your PC; you already paid for it and it will probably work the best.
XP was primarily designed to run on single core machines. If you got an older Socket A computer you can't just run some miracle bios update and put a quad core chip in it. You're also limited by the amount of ram older computers support. You also get into problems with video cards because the amount of AGP video cards that support HD video are limited, a bit buggy, and expensive.
The only new computer I ever had was in the early 90s when my dad bought our family a 386/16mhz with DOS on it. We used to have to make a 3.5" boot disk to use less ram to play games on it. Counting laptops, I have dozen computers in my apartment right now, because I buy them broken and fix them in my spare time. A lot of the computers come without hard drives or have Windows broken on them, so I reinstall the operating system they were designed for and that I have the license for. If I don't have a Windows license for a computer I but linux on it, but even then I put the version of linux that is the most suited for it minding CPU and RAM limitations.