Microsoft Windows XP Home Edition inc. SP2 - OEM - 1Pk - £55
Microsoft Windows XP Professional Edition inc. SP2 - OEM - 1Pk - £90

So what do I get for the extra £35, and is it worth it? (Gamer/Downloading/Surfing... and thats all really )

AND

Is it true that it can only be used on one machine? I remember reading these forums and someone said if you changed machines(upgraded) it would no longer work. Can anyone confirm this?

XP Pro gives you the capability to join a Windows Domain which I doubt you'll ever do so go with XP Home. According to the MS EULA, once an OEM version of Windows is installed on a computer and activated, it is tied to that Motherboard. You can only replace the Motherboard if it dies. It is true that it can only be installed on one computer at a time.

Grumpy

If the mobo dies, you can use it on a new mobo and I've had several "die" on me and never had a problem with activation

3rd person wanna confirm this?

my copy is oem and I have gone from a SOYO motherboard, to a msi, to a asus all using the same cd and cd key and it has worked fine

My full retail XP Home has been reactivated several times, as I upgrade and reformat usually. The last time it was refused on automatic activation. I called the number given and was told I had installed it too many times according to the automatic system, but he would give me new activation numbers, which he did but it was a pain and took a few hours, especially since the last time there was no hardware change at all. Never had a problem before.

Interesting, every time I had to call to reactivate an OEM version took 5 to 10 minutes. It's irritating I had to spend even this amount of time to use something I paid for and was only using on one machine but you learn to live with it since software companies assume their customers are thieves.