Are you currently running XP and considering upgrading to Windows 7 Professional? Is this why you are asking? If so, I'd say if your computer is equipped to handle Windows 7, the upgrade is worth it. Visit http://windows.microsoft.com/en-US/windows7/products/fe... to check out all the features that you get with Windows 7 (many that you do not get with Windows XP). Also, as jefe323 stated, you do get XP Mode with Windows 7 Professional, making it easy for you to still have access to programs / games that are built for XP.
On a side note, if you are considering an upgrade from XP to Windows 7, make sure to run the Upgrade Advisor before installing Windows 7. It will scan your computer and let you know if you need to make any changes before upgrading.
Before doimg a research Xp Pro vs. 7 Pro, Ive heard negative results about 7 Pro. People were saying that 7 pro is a fixed-up Vista Pro combined with Xp Pro. Is that true?
This is a bit odd, I have hardly heard anything bad about 7. In fact most IS people say its the best Microsoft OS ever. Whoever told you this is either a MAC user or uses email and Facebook as their main programs.