i tried a pedometer for a while, but it would reset itself if i hit the wrong button...that being said, the one i had the best luck with was one by sportline's fitness pedometer 360. i think they are normally in the $15ish range, but i got mine used for cheap. i liked that it had more functions than other ones, but i like gadgets.
i know ww had one for a while, but it was pricey, and you could get a better one in target for cheaper.
i found i got better use out of my heart rate monitor though. the things i like to do don't lend themselves to footstep counting.