voltage regulation - pinipilit nya maging stable yung output voltage kahit pa tumaas o bumaba yung input voltage.
power/line conditioning - inaalis nya yung noise sa kuryente. this is just a technical jargon for filtering and most power conditioners dont do voltage regulation even if you see a volt meter on the face plate.
if i were to use an avr and a furman power conditioner at the same time, isasaksak ko muna yung avr tapos sa avr ko isasaksak yung furman.
some of the newer servo avrs also have line conditioning built in so you dont need to buy rackmount conditioners unless you need a fancy light for your rack.
then there are power distribution units like this behringer pl2000 unit
![](http://www.behringer.de/EN/images/products/PL2000_P0247_FrontTopPerspective_web.jpg)
its just a rack mount version of this with a light. buyer beware.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/1/1d/German_power_strip.JPG/800px-German_power_strip.JPG)