How about Fred and Ethel, Lucy and Ricky, Mutt and Jeff, Nip and Tuck, Hop and Skip, Him and Her/She and He, Tweedledum and Tweedledee, Pete and Repeat, Dis'n and Dat'n, Groucho and Harpo, Rhett and Scarlett, Hope and Pray (as in "they don't get lost"), Ap and Ug, or...

...or maybe my ideas are just dumb and dumber.