Getting news that it should be real soon. They still have some lighting problems w/recompiled maps so we might not get them yet (they'll use the old maps w/o clipping and exploit stuff and release the maps when they get them fixed). I know they are working on the linux port and in the past that was always one of the last items to complete. I still don't have a release date but I can smell more haiku's are in the wind.
BTW...the news from Valve's internal tests is really positive (of course...if it were me getting ready to release something I'd be positive too...
). I think it's been good for the internal Valve guys to get away from the constant L4D and TF2 work and doing "different". Kinda that putting on an old warm coat and finding your significant other had the hole in the elbow patched and the lost buttons sewn back on (or use some other lame analogy of your choice).
BTW...yea...on HDR...it really lightens up the interior rooms on most maps so if you have enough hardware to handle it and don't want to screw w/Mr. Gamma it's a decent way to gain a small advantage.