hmmm...this is a question that requires some serious pondering, due to the fact i have seen about every episode 2-3 times.
Hollywood minute with Spade was always one of my favorites.
Norm McDonald, Nealon, and Dennis Miller were all great with weekend update.
Waynes World was probably my overall favorite sketch. As well the only SNL spinoff movie that was ever worth anything, and one of my favorite comedies to date.
I loved the entire early 90s cast, and Will Ferrell, Norm, and Tim Meadows from the past generation. The new cast, Jimmy Fallon is pretty good with Nick Burns, but the majority of the stuff is pretty weak now. Horatio Sans is pretty funny as well as far as the current cast goes.