I'm a (mostly) happy user of a Linux-only (Gentoo) IBM Thinkpad T43.
Currently I'm running Compiz-Fusion 0.6.1... :-) which kind of proves that the fglrx driver works. Performance is not so great though, possibly because of the indirect rendering required, and stability also remains desired. Without Compiz, just using KDE, the fglrx driver (8-3) is rock stable and fast!
Note to ATI: please, please, please implement GLX_EXT_texture_from_pixmap!!!