I have been a linux user for about 7 years now, I am a loyal user of Linux and barely use Windows and I have some very good reasons.
First of all Linux has not been as troublesome to me as Windows has, if there is an issue with it its actually easier to fix (even with the terminal) then Windows.
Secondly it doesnt need a restart for every little security patch or change to the OS, in linux all the components are separate from the kernel and for me this is more of a good thing then a bad thing.
Thirdly Linux is far more easier to modify and customize to my needs, no need for 3rd party projects to customize linux to the way it suits me.
Other things that bug the heck out of me in windows are:
The file browser, I always hated windows explorer for not embracing stuff like tabs like most linux file managers do.
The need to defrag it, NTFS has to be the most broken file system ever created after FAT as it clutters far too easily.
But the top reason why I use linux is Microsoft itself, they are one of the most anti competitive companies out there and have tried to shut down linux many times with false patent claims and intimidation, I only keep windows around for netflix but that is it and might remove it once I get a boxee or something like that.
I have a PS3 but warming it up just for netflix gets tedious
Currently I use Ubuntu 12.04 and very rarely boot into Windows 7 Professional 64bit on my self built machine