Has anyone done this? Anything I should know about before proceeding?

I have a 2011 MacBook Air, and barely tolerate the OS. I use Windows (in various versions) on a home desktop, a work laptop, as well as other computers around the house.

I use the MBA just for the following things:
* surfing the net (using mostly Firefox)
* email (gmail won't work through the web on it, so I use whatever email client it has, but would prefer web gmail through Firefox)
* watching videos (through VLC)
* listening to music (through iTunes...which is the one thing that seems to work well on the machine. iTunes on my desktop pc crashes at least once a week)
* occasional MS Office related stuff (have Mac Office on the computer)
* some printing, through a home network HP printer

The only thing I can think of, off the top, would be I'd need to install Windows Office. I can get an inexpensive license for that through work.

I've given the Mac OS over a year, and it still frustrates me. I know this is a touchy subject; whenever I post about it on FT, I get bombarded with people saying how any Mac OS is better than any Windows. So I'm beyond that, I want to move forward with Windows on the computer, and move on.
Rather than buy a new computer now, I'd like to get another 2-3 years out of this machine, with an OS I can actually use (and not just struggle with). When it comes time to replace, I've already got my eye fixed on a ThinkPad.