There are many reasons Windows XP, as great an operating system as it's been, falls well short of Windows 7. I've listed five of them in this article.
I left out one of the primary reasons -- the Windows 7 Taskbar. That's because I cover it here.
Let me know your reasons for wanting, or using, Windows 7 instead of XP -- or, if you feel so inclined, tell me why I'm wrong.

This is pointless. Why should we not expect W7 to run way faster than its grandparent?
Richard,
The point of the article is to discuss a number of ways Windows 7 is superior to Windows XP. Since many, many people are still using XP, it seemed like a good idea to specify some of those reasons as a way to help the decision-making process.
It is unclear to me, from 20 minutes of research, whether Windows 7 is faster than Windows XP.
It appears it might be, one day, as it has better support for multi-core processors, but it is a really bad show from Microsoft to not make a faster operating system after nearly ten years, if this is what has happened.
Damian,
Windows 7 is faster than Windows Vista. I don’t know about XP. The comparison between speeds of XP and Windows 7 would be hard to make anyway, since almost no one would try to run Windows 7 on hardware built for XP. I know it can be done, as I have some colleagues who have done it; but most people getting Windows 7 will be getting it as part of a new computer.