You've played Clannad? I assume you have, since I think they're more well-known than Little Busters. If you haven't, play it. Very good story. There's Phoenix Wright and Time Hollow for DS. I really recommend Phoenix Wright, it includes more gameplay and generally needs more thinking than most. There's the Higurashi no Naku Koro Ni series if you like horror. It's available on PC, and also on DS and PS2. The art on the PC version is pretty amateurish though. The Umineko no Naku Koro Ni series (PC) is by the same people, also horror. Chaos;Head is also a horror visual novel. If horror isn't your thing, there's still plenty of non-horror ones.
I'm not sure what you mean by Visual Novel... http://shii.org/translate/ That's where I get most of mine, though. One of my favorites is A Dream of Summer
