360 has Lost Odyssey, Magna Carta II, Infinite Undiscovery and more (the usual Final Fantasy crap etc). Although only the first is exclusive, and if you want an "undub" get the Asian (not Japanese) release which has Japanese audio and English sub options (although it's NTSC-J/PAL regions only afaik...but I guess jtag/rgh would probably get around that issue).
Original Xbox doesn't have much that's good. Some people like to mention Phantom Dust but it's total shit honestly.
Metal Wolf Chaos is a decent mecha type game with crazy plot, Japanese exclusive but mostly English anyway and there's a translation for the rest.
Edit:
For some of the titles mentioned in post #2...Sakura Wars So Long My Love is also on Wii, Mega Man Legends is on PC, Zone of the Enders HD Collection is on 360 and PS3.