Grid + Grid Custom Layouts + Clique // Vuhdo // Healbot.
Either of the three options will get you a fixed order (probably alphabetical sort) for your team.
Clique interprets clicks for the Grid route, Vuhdo or Healbot interpret the clicks without another addon.

I like:
Cooldown Count, for the reuse timer on individual buttons.
Deadly Boss Mods, for heroics/raids and pvp timers.
Dot Timer for buffs/debuffs.
Fubar, to have lots of information plugged into it.
Jamba for flights and quests.
Mapster for the world map.
MoveAnything, to rearrange where stuff is.
Pit Bull for my unit frames.
Postal for mail.
Prat for the chat window.
Quest Helper for questing.