I agree that trading in a car is leaving money on the table most of the time. Also, my observation of the used car market at the moment is like Kattie's somewhat. The used car market was DECIMATED by the stupid idiot moronic Cash for Clunkers program, which mandated that every car traded in HAD to be destroyed and shipped off to the cruncher with no parts being salvaged, etc. I got a beater for $4,000 about a year ago, and it took me a LONG time to find something that good. It's probably easing up some now, but not greatly from what I hear.
In general, I agree with buying used, but IF you're driving it like y'all do, Kattie, then that would be worth it. The other reason I have bought new v. used before is when I was living alone and driving a long distance to work. Us single girls give a lot of thought to security, and it was worth it for my peace of mind.
RE: getting the best price - A friend of mine was looking for a new Camry a year or so ago and shopped exclusively online. She e-mailed several dealerships back and forth and took the one who came down the lowest.