For those who don't know - I'm the main Second Life Linux Client developer here at Linden Lab, and I thought it'd be a good idea to give a status report on the Linux Client. I hope that it is of interest - apologies if I am over-wordy!
First, thanks to everyone who has submitted good bug reports here on the forum. I read everything, and many reports have been critical in identifying and eliminating our biggest holes in compatibility and functionality. Keep them coming.

Second, I'd like to re-state what I've said to some folks in the past: everything will be fixed and implemented in due course - we're aiming for nothing less than 100% of the functionality of the other platform clients, 101% of the stability (Linux video/audio drivers permitting!) and as much compatibility as we can reasonably squeeze out of our one-size-fits-all Linux download.
Hopefully, those residents who have been alpha-testing the Linux Client for several months can confirm that we've come a long way on Linux. I think we're at the point where the dozens upon dozens of little annoyances are pretty much ironed-out, and the vast majority of day-to-day features are now implemented. I wouldn't feel bad about moving the Linux Client from Alpha to Beta designation before long.
So what's happening at the moment for the Linux Client?
You may have noticed that exciting new Linux features aren't appearing in the release announcements as often as they were a couple of months ago - this is a good thing, as the simple explanation is that there aren't many user-visible features left unimplemented now! Additionally, we get to implement the Linux version of new features at the same time as for the other platforms, so we're no longer always playing catch-up on Linux.
As we start to move from Alpha to Beta, Linux development focus is shifting more towards improving compatibility and polish rather than raw features, hence the new automated crash-logger and other work similarly too unglamorous for residents to really get excited about, but utterly essential to the long-term quality of the Linux Client. One such wonderful recent behind-the-scenes change to the Linux Client is that we're now integrated into the mainstream build process, so we get synchronised releases, tighter feedback from the Quality Assurance team, and I get to utterly intimidate any developer who accidentally breaks the Linux build.
Feature work is still ongoing, however! Most of our remaining unimplemented features are fairly big jobs, so the work to implement them rolls along in the background over several releases, which is why it looks like we sometimes have a few releases with no clear Linux-specific changes - rest assured that Linux development is constant. Right now I'm mainly working on two things, one of which gives us Linux users the cool HTML Login, embedded Web Profiles, and the essential F1 Help. The other one is the Linux portion of something even more exciting, and that's all I can say about that.

Thanks for your commitment and testing, and we hope that you'll find 2007 to be a particularly exciting and enjoyable year to be part of Second Life!
- Tofu Linden