I use a Mac Mini at work. Two, actually. One with Linux installed, the other with Mac OSX.
The Linux Mini (an original Core Duo 1.6GHz) runs fine but had the annoying habit of freezing the mouse every time I’d type a key. Also, the CAPS wouldn’t light up in X but was fine in the console. After avoiding this for an embarrassingly long time I’ve finally fixed the problem. It turns out that it was an interaction with mouseemu, a package that I _never_ use.
So, if this is bugging you, try:
sudo apt-get-remove mouseemu