This is what I did on my priest:

I use the Addon "grid" which displays your party members, their Hp and any debuffs they get.

I then set my mouse wheel to the following macro:

/cast [nomodifier target=help] renew; shadow word pain

/cast [modifier: shift] Dispel Magic

/cast [modifier: ctrl] Cure Disease

/cast [modifier: alt] Mass Dispell



Basically this macro - when clicked: casts renew on friendly targets or SWP on enemies, when shift+clicked cast dispel magic, when Ctrl+clicked cast Cure disease, and when alt+clicked cast Mass Dispell.

I love how handy this macro was and setting to my mouse wheel meant I could quickly and easily cleanse anyone by simply clicking on their unit frame on Grid and cliking my mouse wheel.

This works great in both pve and pvp situations.