Some of the audio-oriented power conditioners are definitely overpriced, but I do think there is a quality difference between some of the more moderately priced units from companies such as Panamax and the inexpensive computer-oriented surge protectors. Things such as noise filtering, high-current outlets, switched outlets, etc are all useful to have.
One thing you should be aware is that the type of surge-protection used in really cheap surge protectors can limit the amount of current drawn by high-current devices such as multi-channel amps. So even if you don't believe the hype about power "conditioning", I would at least look for a unit that has some outlets specifically marked as being for high-current devices.
I went with one of the Panamax units because it had two high-current outlets, two banks of switched outlets (useful for making sure the pre/pro powers on before the amp/sub), as well as coax filters for UHF/VHF and satellite.
