how to know what power to get-match speakers best?

i dont beleive watts are related to db directly(i beleive db is actually a sound pressure rating)-i think youre speakers specs have more to do with db rating.watts are related to volume because as you increase the volume youre amp has to deliver far more watts(double per increase i beleive)-this is why most receivers and many amps start to produce audible distortion and sometimes clipping when pushed(sometimes just moderately pushed)-and this is why amplifier wattage rating means almost nothing when your talking about most mass market products and many high end products because it doesnt tell you how well the amp can deliver the power as the volume increases.an amperage capability is a far more useful as in the case of harman kardon and nad products which can deliver beetween 20 and 30 amps per channel(vs. probably less than 10 for most recceivers and amps)-amperage is a rating of power as in your home outlet delivers 15 amps and all your electronics list on their backs how many amps they use-this does not mean you need massive amps to make a good amp or receiver though-its really more about good design.if you only need to play music at low to med volume all of the above may be irrelevant but if you need to turn it loud occassionaly i consider the above very important-heres my reccommendations for power delivery based on my admitedly somewhat limited experience--mass market products-hk,nad,yamaha,onkyo,outlaw audio.mid-high end--nad,roksan,chord,calaudio.i highly reccommend the roksan kandy or caspian over the mass market products unless you can find them at about half retail or if your budgets limited or if you need a home theater(vs.stereo)receiver or amp.