When choosing a Japanese kitchen knife there's a few things to consider:
all-rounder: the Gyuto or Santoku - the standard domestic knife in Japan. Technically, the Santoku has a deeper (or taller?) blade, while the gyuto is more slender, and based on a western chef's knife.
veg knife: Nakiri - good for meat as well. Usuba - for traditional Japanese veg prep, wafer thin sheets of daikon radish, that sort of thing.
small knife: Petty
raw fish: Yanagiba (single bevelled)
filleting fish: Deba, Mioroshi, Ajikiri (all single bevelled. Deba is the largest and most substantial, Ajikiri the smallest (named after the aji fish, a kind of mackerel) while Mioroshi is an interesting take on the Deba, with a touch of Gyuto thrown in.
For beginners, think about the stainless steel Tetsuhiro range - they won't blow you away, but are a great introduction to Japanese knives. Beyond that, do you want a more traditional Japanese feel (Masashi's knives and the Rosewood Carbon range all have Japanese style handles) or a heavier, more substantial Western feel (our Western Bubinga and Shigeki range have more familiar western style handles)
White Paper Steel is the easiest to sharpen but Blue Paper Steel holds its edge longer while SLD and VG-10 are hard wearing and semi rust proof (Tadafusa Kobo, Masashi, Shigeki)
Masashi, needless to say, are the nicest...