As a huge linux fan I wish I could say the state of pro-audio on linux was great, but it isn't. There are a few problems.
1) Hardware support -- sound cards we have MOTU, Steinberg, Aardvark etc sell only 10s of thousands in a year, SB Live sells about 100,000 per year, therefore they get drivers, we don't. I do think it is quite stupid that most companies now offer support for OS X but not linux, they could most likely just do a few modifications and then have it done, but not everyone like linux.
2) Software, it's really difficult to program good audio software. It's even more difficult to make it so it can run on any number of platforms. Keep in mind linux runs on a intel/amd box, a PowerPC box, a friggen Mainframe from IBM, and everything in between. There isn't anything really standared about all the hardware, so the software needs to work a bit differently. Additionally, VST and DirectX are quite native to Steinberg and Windows. It would be nice if they were an open standard, but since they are not, you can't use commercially available plugins. So free software isn't really cutting it. I haven't seen any major software say anything about linux either, Cubase SX on linux would rule and I would pay for it, but I don't think it will happen in the near future. However, there is quite a lot of Pro Video stuff being done on linux now, so maybe that will help our cause.
I know I didn't say much, but if its Penguin news, I try to keep up with it. When I find something worthwhile, i will let everyone know.
--MIKE