I'm a huge fan of Deus Ex. It's one of the best mixes of fps, rpg, game-noir ever created. It was kind of like a futuristic version of Thief and included stealth elements, setting traps, special abilities and augmentations. If you've not played this you can buy it on steam these days for an incredibly cheapo price.
The second installment was fairly embarrassing, since early screenshots seemed to promise and exciting game. Unfortunately it appeared to almost kill off the series.
Currently the 3rd game in the series is under construction. This is a prequel of the first game and features a character called "Adam". Now who knows how this will turn out, however there has been a recent visit by one of their forum members which makes me more hopefull about the outcome!
Click here to read the forum post about this (takes you to the DeusEx 3 forum)