Windows 7 is the smooth, reliable, and twice as fast as XP. Use the 64 bit version to utilize more then 2 gig of RAM.
Once you use it XP will be a distant memory. You will NEVER look back.
Good luck.
http://www.elitetrader.com/vb/showthread.php?s=&threadid=182545&perpage=6&pagenumber=1