If I ever want to buy windows 7..
Which one should I get?
There is professional, ultimate and home premium.
I dun really know what is the difference between them. :p
Some advise, please
Windows 7 Home Premium is essentially equivalent to Windows XP Home and Windows Vista Home Premium. It has all the features that a home PC user would need, along with extras like Windows Media Center (for HTPCs), etc.
The Professional version is more for business users, who need features such as joining a domain, backup/restore functionality, and the new virtual Windows XP Mode (for people who have 2D XP programs that don't work right on Vista or 7.).
Windows 7 Ultimate is the "king of all kings" edition, meaning it has all the features of all Windows 7 versions, as well as MUI support (ability to change the language GUI), BitLocker (encryption), and ability to use VHDs (virtual hard drives).
In your case, I think Windows 7 Home Premium will be ideal for you, unless you need a feature like XP Mode for compatibility reasons.
In any case, I've been running Windows 7 RTM since August, and have been lovin' it! It's very snappy and runs more smoothly than either XP or Vista.