Linux?
FreeBSD?
Windows2003?
Other
I heared thad FreeBsd is the best

Personally I do not know but you might also consider the upcoming Vista:

http://www.theosfiles.com/os_windows...ta_Server.html

Clearly Linux.

Hey Guys,

I have widely used Windows XP and I just love it. Vista looks good occupies more space , slows down the system and lot of other issues like Internet etc .... If its fixed Vista is the best but as of now most of the issues occur due to incompatibility ...

I am using windows server 2003 standard edition. It is OK with me. Fits my requirements, then I will commend that!