Windows 7 is actually Windows Vista part 2, it even shows on the M$ version number.
Xp was 5.x - Vista is 6.0 and Win7 is 6.1 so its a gag to sell the Vista product.
I installed Windows 7 Professional a month ago and when you first start you cannot but help fall in love with it as it is VERY fast, and I mean very fast in comparison to XP, BUT........ in boot up and loading only.
Most your applications actually run slower, cursor operations in big documents are pathetic to say the least, and whatever you do don't try and add an additional Xp hard drive so you can dual boot as Win7 will throw all its toys out the cot if it sees another hard drive with another operating system and it will start crashing and hanging up that it makes Win98 look like a Sunday afternoon picnic.
I thought I was going crazy, and have now reformatted the drive 4 times with a whole new install but within a week, all the crap starts again.
You remove the second Xp drive and everything runs smooth again.
As for the Xp-Mode they brag about, it still does not see the graphics card which renders that another useless selling point.
Many of your older games will lockup or crash and at the end of the day its R2400 odd down the drain, maybe around SP2 it might be a consideration.
It has many plus points like the networking facilities are great and so are many other things, but if you are a serious gamer (new and old) or a developer, you may be in for a disappointment.
I am still using it now with a single hard drive only as I want to get to know it well, but I think unless M$ bring out a serious Xp compatible mode, I will be switching back to Xp in the end.