vordrax: ... started hungering for some classic, solid stealth action without RPG elements getting in the way.
You could try Splinter Cell if you haven't already?
http://www.gog.com/gamecard/splinter_cell It's currently 4.99 and great fun if you're into ghosting with the odd takedown.
Hitman 2 is on here too, no Blood Money though. ;_; And it's at the same price as Thief. Still, the ability to shoot everyone in the level and get an undetected mark at the end is hilarious. Chronicles of Riddick is half price at 7.49? Has some RPG cut scenes, but it's great fun. You can spend 20mn sneaking through duct systems avoiding everyone, finally get bored and come out near a guard. Pump a shotgun into his back then stalk from room to room with an Armalite AR-10 Carbine-gas semiautomatic, bitterly pumping round after round into guards and co-prisoners.
Somewhat Deus Ex'y in it's ability to seamlessly switch from complete stealth to all out carnage. Either way, there's a few good stealth games on here to tide you over till Thief goes on sale.