Heh, I have like 10 keys on my pally all set to a basic "/startattack" macro. As an example of what stuff I have where:

priest+locks group
1 = cannibalize (all 5)
2 = nothing (locks), prayer of healing (priest)
3 = /petattack (locks), PW:Shield/PoMending (priest)
4 = /petpassive (locks), PoMending (priest)
5 = Seed (locks), PoMending (priest)
6 = Hellfire nochannel macro (locks), PoHealing (priest)
---
Z = fear round-robin (locks), PoMending (priest)
V = AoE round-robin fear (all 5; resets in 25 secs or something back to the priest psychic scream)
X =
C = deathcoil round-robin (locks), PoMending (priest)
B = nothing (locks), CoHealing (priest)
---
G = MORE DOTS! MORE DOTS! macros (locks), PoMending (priest)
H = wands (locks), PoMending (priest)
---
Q = WoTF (all 5) FTW! :P
W = drain life (locks), PoMending (priest)
R = lifetap (locks), nothing (priest)

The mages+pally are kinda similar.

1 = cannibalize
2 = mana gem use/create macro
3 = nothing (mages), wisdom/judgement/startattack macro (pally)
4 = CoC (mages), /startattack (pally)
Q = WoTF (mages), Divine Shield (pally)
W = can't remember lol
R = Blast wave (mages), /startattack (pally)
Z = sheep round-robin (mages), /stopattack (pally)
X = PoM/Pyro (mages), /rofl (pally)
C = frost nova round-robin (mages), /startattack pally
V = Arcane pwnage (mages), /rofl /startattack (pally)
B = bubble (mages), nothing (pally)

There's more, but that's the stuff I use all the time. The rest is edge-case setups for things like zerg pulls in instances, spread out macros, etc.