the two companies that can do no wrong so far (as folders)...
chris reeve
benchmade
there are other companies that I'd love to have on this list but have sadly fallen off due blade slop (emerson, strider). not always, and when its not there they are brilliant, but I always have to worry and cross my fingers when purchasing.
spyderco makes some great knives but often fall short IMO on tip strength (again, not on all their knives but a few that could have been perfect like the para and earlier delica)
As far as fixed blades I'll say strider and swamp rat since they're the only ones I've owned and they have impressed me a great deal.