Of the lenses I own, the 50 f/1.4 and the 135 f/2 are my favorites.
Of the lenses I don't own... favorites are 17mm TSE, 35mm f/1.4, 65mm macro, 85mm f/1.2, 100mm macro, 200mm f/2 (duh).
How could anyone not have 200mm f/2 be a favorite?? I mean, aside from the fact that you'll never own one because of the price? ;-)
I have a 16-35mm f/2.8, but I don't like the distortion. Otherwise it's decent... not amazing, but sufficient to get the job done.