I wouldn't say I have "a lot" of applications installed, although I'm not too sure how to quantify that. I assumed it WinSxS related as the other reply mention

I wouldn't say I have "a lot" of applications installed, although I'm not too sure how to quantify that. I assumed it WinSxS related as the other reply mentions, and upon investigation found that it is 9GB alone! I don't run Windows outside of work so I've just never really bothered looking into it, but if it continues to balloon I guess I'll have to.