People who say this really don't know what their talking about. It's like saying Ashphalt sucks because you own a boat. Windows, Linux, OSX, ect all have their good points and bad points. Both have their place in the computer world.
Windows is good for gaming, has the most programs written for it, very user friendly and is backed by a multi-trillion dollar company. It's downsides are that it is prone to viruses and errors, but really if you know how to operate a computer correctly, this isn't really a downside(vista is still error prone regardless
wink ).
Linus/OSX is good for actual computing. Writing programs, running servers, hacking, ect but it sucks for gaming and applications in general and isn't user friendly. One up side to Linux is that you can find programs to do just about anything for free.
It comes down to what you prefer to do on your computer tbh.