Weirdly enough, I still play Perfect Dark every single day. Perhaps it's just nostalgia, but fuck it, it's still fun! Timesplitters 2 is better though.
However, Deus Ex, that which so astounded me back in 2000, has aged about as well as cream does if you leave it in the sun. The AI is jaw droppingly terrible. They're all freaking myopic! The graphics, inconsequential as they may be, have not aged well, the gunplay is horrible, the acting has only got worse with age. It's just bad now, which is depressing, because back when it came out, it was revolutionary. I suppose everyone just copied its great ideas, and did it better. Such is life.