Hmm, I've had this computer since mid-Feburary and I haven't had to clean it out yet. I have 2 80MM case fans, one on the side, one on the top. The side one blows air in while the top exhales. I also took off the fan guards because it increased air flow by atleast 50%
I see a little bit of dust on the CPU fan, NB fan, and video card fan, while there isn't much on either of the case fans. Then again, I really never turn my computer off so I dont get a close look.