Just over a year ago, Greg Kroah-Hartman announced the Linux Driver Project - companies could get Linux drivers written for their hardware free of charge, if they provided specifications (possibly under NDA). There is now an April 2008 Status Report for the project - they are short of companies and hardware to write drivers for. This is probably because Linux hardware support is excellent in all but a few specific areas - there is some interesting discussion of the efforts being made to support wireless devices and graphics cards later on in the thread. (If you're looking to get involved with Linux kernel development, cleaning up greg's LDP git tree would be a good place to start.)

Speaking of graphics drivers, VIA appears to be following Intel and ATI in releasing the necessary documentation to write good drivers for its chipsets. Suddenly the future is looking quite bright for Linux hardware support - almost all hardware will already work out of the box, and things are only improving over the next couple of years.