I got this for a new hard drive and to move away from Vista, and yes I agree with most, this should of been a free upgrade for all users of what is a flawed OS in Vista, isn't like Microsoft couldn't afford to do that for their loyal users either!
Anyway, most of it has been said, a great Operating System, better than both XP and Vista although for most things XP is fine.
I've read reviews about if you can afford it go for Ultimate, the only main difference between Ultimate and other versions is your entire system is encrypted.
Compared to Home Premium you can't use XP mode, connect to company networks, you can't back up to a company network, you don't get bitlocker encryption or able to work in a choice of 35 languages, in Ultimate you can, but do you need to, answer 99.99% of the time, NO.
SO unless you need those few extra features, save 50% of the cost and get Home Premium.
If like me you have a business with 20 years worth of info on your machine it's probably worth a bit extra to keep it safer but I've never been attacked anyway so I may as well of gone for Home Premium, I can only speak English too etc.
Installed quickly, about 30 mins.
Problems running Battlefield 3 on Vista 32 bit, all gone using Win 7 64 bit, along with various other issues, you could be thinking your graphics cards have had it as I did, or your MB, RAM, what the heck is wrong!!!! etc etc but the new OS proved otherwise, unless you can rule the OS out which you can't if you are using Vista you can't then work towards what the issue is and curing it.
Be aware, you cannot run Win 7 on any pc, you can download and run the Win 7 advisor but that does not tell you if your motherboard can run it, something I was unaware of as it isn't stated anywhere, you can search on Microsoft for compatible motherboards so do that, the advisor will automatically check the rest of your hardware but not that part.
I tried the bitlocker encryption but that deosn't work either as you need a motherboard with that feature built into it, so I wasted an extra £80 on Ultimate for nothing.