Moriarty, I was at Denver this past week, the terminal is beautiful and most of it is designed to move folks along, but if you have a commuter flight (like I did) out at gate A87, you are in for a long, long walk.
Rapid City was mentioned earlier, I was also there and concur with the writer, very easy to get into and out of, but like most small airports you going to connect in Chicago, Denver, or Salt Lake City in most cases.
For me airports tend to blur together (I’m up to 110 visited to date), but my votes are:
USA:
BIG AIRPORTS–Atlanta, for all the complaints, moves massive numbers of people efficiently and well, with plently of amenities at all the terminals.
MEDIUM AIRPORTS-Birmingham, AL and Hartford, CT both have reasonable walks to the gates, good selection of shops past security, and not many holdups.
SMALL AIRPORTS-Like Rapid City above, my hometown airport of Huntsville, AL has only 8-10 gates, is easy to get to, and besides the major hubs, it also services Washington, DC.
INTERNATIONAL AIRPORTS–Singapore and Amsterdam have been mentioned before and all I can do is second them both. And regarding public transportation to airports, most European and a lot of Asian airports have such transportation–In Shanghai you get to go 420km/hr on the Maglev train to the airport.
AVOID AT ALL COSTS: IN the USA, LaGuardia; Overseas Paris Charles DeGaulle. You have been warned.