I do own one for one game though, that being Steel Battalion.

Ditto on that one. I bought SB before I even bought an Xbox. The only reason I got the Xbox was for that game.
The Xbox is great, and I've got a lot of entertainment out of it with other games as well.

Picking just one system is tough for me, there are pros and cons to each of them, and I honestly can't think of a reason why (or why not) to get one over the other. Sure, you all have made valid arguments for going with a certain system, but I think it really comes down to the type of "gamer" the intended party is.

As for myself, I'll be picking up a GC and a PS2 sometime in the next few months. There are just too many games that I want to play that are spread out over all three systems, and I would rather not be limited.