I'm very similar to others, in that I have a few basic keys that cover all teams with similar actions, and then I have the rest just wherever.

1-6 = heals based on [@party1], etc. so I'm always healing/decursing the right toon based on the party bars.
V = normal DPS spam
G = oh shit DPS spam
H = major offensive cooldown stacking
Y = major defensive cooldown stacking
Z = round-robin CC
X = alternate CC or other offensive specialty spell
C = mass AoE _OR_ round-robin AoE CC (depending on team)
Q = trinket or other anti-CC
R = cleanse/purge/etc.
W = IWT
B = daily quest items, quest mounts, etc.
E = move forward on main toon, /follow on slaves
D/F/A/S = left right strafe/backward/sit
SHIFT+G = long-cooldown or proc-based offensive moves
SHIFT+R = long-cooldown or specialty defensive moves and AoE oh-shit taunts
SHIFT+V = targeted AoE (rain of fire, blizzard, bombs, targeted dailies, etc.)
J/alt+J = mount/dismount
CTRL+= = hearth/LFGTeleport()
-/= = drink/eat
NUMPAD keys = specialty macros, like the mounted setup for the last boss in Occulus.

You can ignore the specific keys (mine are all based around my left hand always being on the home row by default) and just worry about the classes of abilities. With a bit of knowledge of macro writing (tons of examples already) you can stack a lot of things on a few keys to make them easily accessible. Some things you'll want on single/dedicated keys because you don't want to have to think as much about them, such as healing your party. Sure, fancy schmancy clickboxes mean you don't have to spend the time doing macros but I prefer doing that sort of thing with a more reliable keystroke. It's all about putting the important stuff on keys you are comfortable with accessing in the heat of battle without as much conscious distraction.