I'm currently deployed. And from what I've seen are a few things. Most soldiers use their laptop to either play games, watch movies, or surf the net. Be that said, we've also had our share of flying dirt/dust and trying to cram the thing in a bag with all the other gear we're issued as we move from place to place.
I've seen screens crack, shells crack or chip off, and the occasional power cord plugin break off.
My best advise, get a small laptop or a netbook of some type. They're usually cheaper and will do most of the things you want it to do. Plus it being small makes carrying it a breeze.
If you're going to be a gamer with the latest and greatest PC games out there, obviously a netbook won't cover it. So you'll probably want to look for something more along the lines of a Dell (mil discount), HP (mil discount), or ASUS that can handle those new game requirements (Processor speed, RAM, and Harddrive Space).

Also, if you're going to be deploying, get yourself at least 1 TB portable drive. Use it for your movies, music, or backup. I have two and both have came in handy many times.