Dispell Magic (priest)
 

I know there are addons that check party members and such and dispells as needed, but is there one that checks your target for buffs and dispells those as well? Say I targeted an enemy priest and he had PW:F on, is there something that would auto-dispell that?

I don't believe so. As priests can't see enemies' buffs. (only Debuffs). Mages can see beneficial spells with the use of Detect Magic (I think)