There just aren't enough games on XBox that I like that I can't already get on PS2 and I don't wanna have to chip one to get everything that a Dreamcast already does on its own (albeit slightly slower). I'm sure PLENTY of people are gonna vocally disagree with that, but I still stick by that opinion. There may be only 1 or 2 games in the entire XBox library that I like that I can't find somewhere else. However, there are plenty of Playstation games (both 1 and 2) that I can't get on XBox.
I could go off at length on why the xbox is better than the PS2 but I'll simply say hardware specs, hard drive, and networking.
PS2 has some sweet games but the PS2 does not have a single game that graphically looks better on the PS2 than it does on the xbox.
Dreamcast cost about the same as a good chip for the xbox so thats a valid point plus you still need the xbox. But there are many more emulators available for the xbox then for the DC and the Xbox is a great base for a media center device. Not only can it play DVD's but it can play most any video format available on a PC.
The xbox can play most PS1 games very well. If you want you can even plug your PS1 controller (with an adaptor) into the xbox.
Edit: The poll is now pointless since the choices changed. I voted before but now the choices are different and I can't change my vote.