Skip, if you're talking about a so-called "power conditioner" rather than a surge suppressor which is available for $20-$30, the answer is no, it isn't worth it in nearly all circumstances. The power supply section of receiver/amplifiers has a transformer, rectifier and filter capacitors which "condition" the AC from the wall outlet and supply clean DC for the amplifier section to use; nothing more should be necessary.

-----------------------------------

Enjoy the music, not the equipment.