Amazing recovery job! And yes, you're right, it does look a little water-colorish - but as an art piece it works well. The artsy part of it is probably what railpix liked.

It almost looks like one of those extreme High Dynamic Range photos (key point: luminous shadows), but I'm sure you didn't have multiple exposures to work with. I've tried stuff like that (with other programs, not Photoshop) but have never been able to bring back something as underexposed as this. Did you use any particular technique or is this just some standard PS processing?