Hi-Fi Power Conditioner ?

Richard Gray makes a good technically sound pc for a fair price, assuming that what you need is an ac grunge eater. An industrial priced isolation transformer on the upstream side like the one Krell man noted (Sola makes a good one too), follwed by an RG 400 would be a pretty sweet set up to pretty much cover all the bases for not ridiculous $'s. I'd probably buy one (whichever is cheapest) and then evaluate before buying the second component. Much depends on what type of power problem you have (incoming line fluctuations or noise, grunge produced by one stereo component effecting others, etc.).

Oyaide outlet, Richard Gray Substation along with RG600 pole pig works great for me.
Between them they improve the music and video, protect and extend the equipment life with clean steady power, and help stretch the amp draw from a single outlet.

I recommend a PS Audio Power Plant Premier for your digital end and a Shunyata Research Hydra 6 or Hydra 8 for your amps. If you can't swing a Power Plant for the digital end I recommend a PS Audio Quintessence (on sale right now on AudioAdvisor). It's what I use and the noise floor has dropped away dramatically. Super quiet.

BPT would be a good choice, if you can find one used. They do a lot of things well and for the money are tough to beat. They are also very well built.

I agree with Macdadtexas. I also own an APC S15 power conditioner and it is the best purchase I have made in many months. You don't want a blackout damaging something in your system. And the sound is good too! Priceless is not an exaggeration.