Surround sound on Linux finally works. And it doesn't require advanced terminal voodoo either.
For Ubuntu 9.10 (Karmic) users simply head over to the Hardware tab in your sound preferences and select the appropriate profile for your sound device. You'll hear a skip if you're currently playing something on your speakers but that's just the profile switch and is perfectly normal. Users on Ubuntu older than Karmic might want to refer to this forum thread.
There's a small catch though. For me, merely switching the profile wasn't enough. For some reason, the rear left and right speakers were muted and I had to enable it using alsamixer from terminal.
Listing my rear left, rear right and front speakers all as "speaker" doesn't help either (see screenshot, below). I was expecting something along the lines of "rear left", "rear right", "front left", and "front right".
They really need to list speakers in a more easily distinguishable manner. For a while there I was wondering if I had the wrong device since the sound provided by Azalia is listed separately from the HDMI audio provided by the HD3200 chip. It took a while of searching to find that I could manually select the selected device by adding a -c cardnumber to the command.
Well. At least I learnt something new.
As for sound device configuration. It's nowhere near as complicated as manually editing a bunch of configuration files in strange locations and filing them with exotic language that only driver developers know. That's just how far Linux has come in terms of usability. Even the lowly end user can change their sound configuration without too much trouble.