My favorite is for instrument approaches:
Position - Where am I, and what's happening next? Kick-start situational awareness.
ATIS(/AWOS/whatever weather)
Instruments - set altimeter, set DG to compass
Nav radios - Set up everything possible. Nav1, Nav2, GPS, DME, ADF.
Com radios - Ready tower/CTAF in com1 standby or com2
Approach briefing - Altitudes, headings, everything else on the plate.
Landing checklist - GUMPSS
Listen for your approach clearance.
Oh, and speaking of Nav radios... TITS!
Tune
Identify
Twist OBS
Set markers
And of course, GUMPSS.
Gas - proper tank, pump on if req.
Undercarriage - Down and locked, tires checked if visible
Mixture - Rich or as appropriate
Prop - Full forward when below governing range
Switches - Landing lights on
Seat belts and doors - secure.
The four C's, for go-arounds and missed approaches:
Climb it - full power, pitch up
Clean it - flaps, gear, flaps, flaps
Cool it - Cowl flaps open
Call it - radio call to tower/CTAF/Center
Pre-takeoff, I do three things which are kinda redundant but get everything done: GUMPSS (tank/pump, three greens showing, set, forward, switches/belts/doors); Lights-Camera-Action (lights on, txp ALT, call tower/CTAF) and then the 5 T's as I'm pulling on the runway. Turn onto the runway, Time off, Twist heading bug and double-check runway heading, Talk to CTAF, Throttle up.
On the takeoff roll, call out airspeed alive and engine gauges green.
I like Ed's multi-engine thing too, but I can't remember what it all stands for any more.