I would recommend going with something running one of AMD's new C-350 chips if you're set on a netbook-sized device. If you're open to a 14-15" machine, I'd look at their new A4/A6/A8 APUs.
These all have decent GPUs, which is important when playing Minecraft - and have the CPU power sufficient to run both DF and MC quite well. (Most things these days have enough CPU power for everything, except for Intel's Atoms - they're a little anemic - by design - it is the GPU that is the critical component - where Intel falls behind)
If you're open to a slightly rugged case design, I'd recommend Lenovo Thinkpads.
Thinkpad X120e if you want the C-350 (11.6" screen) Netbook-sized device.
Thinkpad E425/E525 if you want a 14"/15" full-up laptop. (Difference: screen size. E425 = 14", E525 = 15")
The Ex25 models will be faster and have a slightly beefier GPU, at the cost of larger physical size and weight.
Only thing I could maybe consider upgrading on them is adding more RAM - 2GB on the X120e should be sufficient, but more is always nice. (4GB should be sufficient in either machine for your needs, unless you're going to start compiling stuff, or hosting a large MC server for your squadmates)
Add external HD for backups, and maybe a spare battery/wall charger - and you should be set. Input devices of choice, along with headphones. Built-in mic and webcam work great for communicating with folks via Skype, TeamSpeak, or any other voice/video system. (I have the Edge AMD 14" and 15" models from 2010, and love 'em both)