I don't know, for a game that I want SO badly as I do Deus Ex : IW, I never tend to play a demo. The level(s) you get in the demo are always spoiled, and sometimes they're out of context, and it just gives me a "yawn, not this level" once I play the final version and I come to the demo level.
Besides, playing KotOR and soon X2, I doubt I'll have much time for this demo anyways. Hordes of the Underdark comes out in two weeks as well, when am I going to play all this stuff?
I've got four days off next week though, only have to work monday, so I'm thinking KotOR is going to see a lot of action. Hopefully they'll get X2 in the stores before Thanksgiving as well.
Creston, who will buy Deus Ex no matter what.