My favorite switch is the red one on the Elite-style on the side of the machine. I think I like it mosty because my parents had Soft 'n Light when I was a baby, and I used it ALOT! Plus it also has a short (CLIK) noise before the motor turns on. Plus the soft-cover bag is right next to it! I'm going to some Goodwills tomorrow with my grandpa and I'm on the lookout for a Elite. I really miss the soft-cover bag. My Oreck just doesn't fill that spot anymore.
My 2ed favorite is the old Convertible switch, where it makes the really loud click and then slowly turns on.
Then I also love the Eureka's/Sanitaire's switch on the base. It just feels like the right spot and size.