First thing I have to say is: If you can afford it, GO MAC!
However, if you can’t, or don’t want to run OSX, here are my thoughts on the different operating systems for PCs:
Linux
Are you really good with computers and think you are ready to try something new for fun? If I were you, I’d try out Linux; it is free after all…. Keep in mind though, you may have to do some work to get the programs you use working, or have to get used to alternative programs. However, once you get used to the new layout and the new way of getting things done, I think you will be pleased, maybe even ready to try a different distribution.
Windows
Are you new to computer? Are you too lazy to try something new and have to re-learn a few things? This operating system is for you!
Free BSD
I recommend this for highly trained computer geeks that are willing to workout issues and maybe even help write some patches for it.
One more thing I have to say is: Cut it out with this “it isn’t compatible” crap… Everything is compatible with Linux, you just need to take the time to figure out HOW!