I still haven't played the original Deus Ex, but I have played the sequel, still can't figure out why so many people gave it bad reviews, Xplay gave it a 5/5 if I remember correctly, and I find they're usually dead on; plus I played it and it r0x0red. B)
Because the first one is better than the second in almost every department, especially in character development and story. Heck, it even won more GOTY-awards than KotOR.
Play the first one, you should find it for a mere 8