If you have Windows 7, I don't see the point of upgrading. However, if you're on XP, I would make the move to Windows 7 or Windows 8. (Windows XP goes out of extended support in less than a year or two. You have downgrade rights with Windows 8 Pro. So you can get Win 8 Pro on a new computer and downgrade to Windows 7 if desired.
Another thing is that BitLocker Disk Encryption is now on Windows 8 Pro as well. Bitlocker was only available on 7 Ultimate or 7 Enterprise before.