I *love* taking my laptop to Burning Man. I DJ off of it. I usually haul out my laptop and external hard drive. After about 4 years of dust, DJing at noon without shade, and other stupid tricks, the drive bus finally went kaput on me. I *could* still use it by booting from a LiveCD or USB key, and I might.
There are some pretty good milspec computers on Ebay every so often, and that will probably be my next acquisition.
Compressed air is your friend. Learn how to take the case apart and blow out everything. The thing that helped me during my stays at Black Rock City was not trying to keep the laptop clean all the time. Trying to wipe the screen or keep dust out was not only futile but counterproductive, depending on what I tried to clean the screen with. Finally, I just let it get dirty. Once I got it home, we went out to the backyard and went crazy with the compressor. I'm really surprised it lasted THAT long.
I'm looking to design a new machine case with a touch screen and modified cooling fan system. I'll post when it actually happens.