I had a sweet half step set up a few years ago (46/49 in front and 13-36 9 speed in back) and it was great fun from a theoretical standpoint but I lived in hilly territory and I got a crick in my neck from toying with the shifters all the time.
I live in the flats now and I've picked up a 50/45/36 crankset. Maybe I'll try it again. I also have a 36/48 crankset that might be just as good for my purposes but having those two close ratio rings would ad just that much more flexibility and consistency to my cadence.