Excellent post. One little thing to add. Like you said, the walkaround starts in the cockpit. Check if the previous pilot left the airplane the way it's supposed to be left. Particularly: mixture off, magnetos off and key out, masters off, transponder standby, lights off.
All too often I get into an airplane and find that the whole Christmas tree, both inside and out, lights up when I turn the battery master on. Not to mention magnetos and mixture.
Oh, and I always do two walkarounds. One quick one to check the lights and the (electric) stall warner, then I reach in to turn the lights and master off, then I do a second round to check all the mechanics. Saves battery consumption.
As for the 2nd, 3rd and so on walkaround of the day: Fuel (check sufficient - no need to drain for water if you have not refueled), oil, tires and anything obvious dangling around or dripping.
Last edited by BackPacker; 19th October 2012 at 11:03.