I'm looking to buy windows 7, but don't know which version to get, so any advice appreciated 
Also is there a version which you can install multiple times ? or are they all restricted to installing on one system only ?
I have my main desktop which is currently running XP and 2 laptops on Vista, i also have a laptop on Win 7 and i find the speed difference etc amazing compared to Vista !
I will also be updating my desktop spec in the near future, so if i can i would like to upgrade all my systems to Win 7
Thanks

Also is there a version which you can install multiple times ? or are they all restricted to installing on one system only ?
I have my main desktop which is currently running XP and 2 laptops on Vista, i also have a laptop on Win 7 and i find the speed difference etc amazing compared to Vista !
I will also be updating my desktop spec in the near future, so if i can i would like to upgrade all my systems to Win 7

Thanks