An absolute must buy. This game has so many elements to it I felt I had to try it out and I was not disappointed.
I'm not a massive fan of FPS games, especially on console, but between the sneaking, action and RPG-type choices it thoroughly kept me entertained, even more so with the extra content that the directors cut has to offer, which has been seemingly integrated with the original story.
While I don't like to play games over and over again, I felt that Deus Ex had a lot of replayability to it, with the amount of choices there are to make I felt like I'd have to play it at least 2 more times to get the full feel of what can really help or hinder you with what choices you've made in your game, and while there are choices that may not make a big difference there are others in which you'll think 'what if I did/said this instead?'
Again, a definite must buy, even if you aren't an avid first person shooter fan like myself, you'll definitely enjoy what this has to offer.