In addition to what's been said...also some of these might be in production, as well as might not be pure adventures:
Grim Fandango
L.A. Noire - consoles - in development
Sadness - Nintendo Wii - in development
Hotel Dusk - Nintendo DS - brilliant game
The Disenfranchised - my own game, I haven't announced it yet but it's a black and white non-comic Noir game - PC only
Adventures in Purgatory - in development and made with Torque:
http://www.garagegames.com/mg/snapsh...w.php?qid=1040
The Late Call - in development and made with Unity:
http://www.bydesigngames.com/tlc/index.html
There's also a new Phillip Marlowe film set in the 40s (starring Clive Owen and complete with narration) and a TV series set in modern times. There's supposedly some movement on the games with the Marlowe character, and it's perfect for a series of games ala Nancy Drew or Agatha Christie. That might be a potential one to look out for.