Playstation has a number of games that interest me, not just FF/DQ. See: Ico, Collosus, Katamari, Kingdom Hearts, Virtua Fighter, Okami, plus about 20 other Japanese RPGs... Xbox, not as much, so many of the games go to PC, but there are still a few games from Rare, Sega and Tecmo I'd like to play on them.
In spite of all that, the only likely reason for me to buy a second system is if Wii pulls a Nintendo 64 on me. I guess I kind of agree with Kairon: why would I want to spend $400 or even $200 on new hardware when I can buy several games instead?