For me:
-real blades (seems to be a running theme here
)
-good assortment not only of knives in general, but of different types (eg. combat, boot, folding, etc); I hate it when there are a dozen versions of a freakin' folding knife and that's it
-Oriental/ancient-style weaponry (katanas, gladiuses?); for me, most European swords just don't do it