Well, i have a large xbox library, as in a couple hundred games, and I plan on keeping them because I'm a collector..
So if the 360 was fully backwards compatible, then I wouldn't have this dilemma..
But they screwed that up, so I don't really WANT another monster xbox.. but I need to preserve all that software for my collection. And if my current xbox breaks, then I'm beat..
But you're right I don't really want both, and a slim ps2 would be perfect, I'd even buy it new.. but see above issue with lots of xbox software and bad backwards compat...
The ps3 will take care of preserving my ps2 library...
-Mike