For desktops I tend to prefer to build myself, I didn't happen to build my current desktop, but it was a homebuilt rig. I've had very good luck with building, but there again it's a matter of 'how much can I afford?' with a dose of google to check for major problems.

I've liked how nicely Ubuntu treats my nVidia graphics card for instance, it detected and automatically offered to install the proprietary driver should I want it, and graphics seems to be one of the major headaches if it doesn't work right.

I find Toshiba makes nice, but expensive laptops, but if I were you, I'd investigate Acer.