|There would be no reason to stay with xp 64 bit.|
Problem is that xp is having trouble keeping up with modern hardware.
If you could get W7 cheap then you may be able to build a system. I'd suggest that you consider some bare setup that has W7 on it. Then add in ram or better video or such to suite what you want.
If your hardware is working then you may be able to stay with xp for a few more years. I have a 10 year old dell that still works fine for internet use.
1/3 of highway deaths are caused by drunks. The rest are by people who can't drive any better than a drunk.