I have W7 Home Premium on my laptop and as I’m a student I can get a upgrade to W7 Ultimate and Office Pro Plus 2010 for £90 :o I offer which I can’t turn down 
What I want to know is will I have to do a clean install or would I be able to put my new product key in the Windows Anytime Upgrade program and then be able to get all the new features?
I think you may be able to just upgrade, and not have to to reinstall.
There isn’t much difference between Premium and Ultimate, though.
Cheers
Ah I’ve found something quite neat.
If you buy a new version of Windows you can just use your product key off the back of the box in Window Anytime Update (even though It’s not an Anytime Update Key) It takes around 10 Mins to reconfigure Windows and you don’t need to instert the Installation Media. I never relised that you could do that ;D
Pretty Neat, No point paying more for a Windows Anytime Upgrade key when some people (Students, Teachers, Doctors ect) can pay less for a full version (due to disconts) and just use the product key off the back of the box