AMD Catalyst 11.10 / fglrx 8.90 series has "early look" Ubuntu 11.10 support (even though it's been in since the fglrx 8.89 series), production-rated support for Red Hat Enterprise Linux 5.7, and 2D performance improvements for the AMD Brazos platform.
There's also a few bug-fixes in this month's driver, including a segmentation fault fix under Ubuntu 11.04 64-bit, among other things. Also fixed up in AMD Catalyst 11.10 for Linux is addressing corruption issues when using the GNOME Shell. Those are just the changes I am aware of, with AMD not publicly pushing out release notes / change-logs any longer for their Linux binary blob.
This latest Linux graphics driver can be downloaded from this page for x86/x86_64 Linux.