Vesperia loads pretty quick on the HD (dunno how it is on disc, never tried). The battles load time isn't instant, but close enough (2-3 seconds). I recommend it.
I have a crappy 20gb HD, but I end up installing all my games anyway. I only really play one or two at a time, so I can handle the space. The install time isn't too bad either. It does suck when playing multiple disc RPGs though...
Anyway, seems I have another game I'll have to check out (Lunar). Done by the people behind Grandia, I'm interested.







