Some systems must be buggier than others. I've had to do no maintenance to my system in almost two years with XP. I am overdue for a reformat/reinstall since it is a bit less snappy than it should be for my quad core but it's not bad.
What kind of stuff are you referring to though?
My XP "sails" through everything as well provided I don't let it get broken and keep good virus protection on there.
Most of the problems were with video encoding programs. I tried WinDVD Creator, Roxio, Nero and a couple others and my system got worse and worse til I ended up reinstalling Windows. If I installed Nero first then Office 2003 afterward the Office installer would break something in Nero. Also my Logitech Keyboard always acted up. Come to think of it the problems were probably because of third party software. I didn't know about System File checker til about a year and a half ago. Since I found that I haven't had to reinstall Windows once.
Now I use ConvertXtoDVD and ImgBurn and they give me no headaches at all. They just work right.
I don't know what is up with my wife's laptop though. All she ever does is some web surfing, webmail and listens to a little music on it. She doesn't go to questionable websites. In the past few weeks I've had to run System File Checker twice. The second time that wouldn't work til after I ran Check disk. Hers came with Vista and I added a second partition and installed XP on that. She hated Vista and refused to use it at all. I got drivers from Dell for XP on her hardware but maybe XP still doesn't like her laptop. It's mostly ATI hardware. If the network gets balky the problem is always coming from her XP. I've always been able to get it to connect using the IP Address. That seems to jump start it and it works right for a while afterward.
Most likely the problems I had were because I was a newby. Her laptop is still puzzling me though. Maybe W7 is working so well because I know how to run it now. But you have to admit it is truly a sweet operating system.