That's a very good spec!
Although I would take a look at :
With an X2 3800+, it's £840. The PC will last a lot longer, you'll probably get another year or so out of the extra £40.
A 3800+ X2 is 2 (that's right) 2ghz cores stuck together. As we go into the future, processes will become more multi-threaded, so they can take advantage of it more.
Compared these :
3800+ = £234 (http://www.scan.co.uk/Products/Produ...oductID=256882
3500+ = £147 (http://www.scan.co.uk/Products/Produ...oductID=152503
3700+ = £155 (http://www.scan.co.uk/Products/Produ...oductID=211678
The PC at the top will contain one of the second two. The PC I have given you a link to will contain the top one. So, you'll get much better value for money!
If you add the second one to the basket with Windows XP, it comes to £840! So, you save around £50, and get an extra year of life or so!
Then again, even if you get the top one, he will be one lucky kid! I wouldn't mind one of those!