OK. This would be a 2 part answer. Favorite meaning which one do I use the most. And favorite meaning which one is the coolest one I have: the one I handle, think about and heft (but in this case is so nice, I have yet to really abuse).
Favorite knife for everyday use-
I use a Mora 510 and 511 more than any other knife in the woods. They are cheap, good, and easily sharpened.
(next in line would be the Condor Kephart which I am using more and more)
Favorite knife (coolest and brings me a smile everytime I look at it-
Chris Reeve Green Beret. It is 7? bladed monster in S35VN with micarta scales.
But ask me in 6 months and it might change