I used to feel the same way, since finding in c. 2006 that using an ATI card with Linux was pretty much impossible. However, this all changed when I built a new machine last year, and wanted 3 monitors. Two monitors worked great with Nvidia; 3 was impossible. I've found that, although still a little buggy, 3 monitors w/ Ubuntu, ATI/AMD graphics card and "EyeFinity" works great (on KDE at least):
http://wiki.cchtml.com/index.php/Ubuntu_Precise_Installation...
Note that you must use a single graphics card for this, which therefore must support 3 monitors. And in response to the grandparent -- I had the same issues with the order of monitors. Luckily they were all identical, so I just swapped the plugs.