After way too much looking around (I was on vacation), I decided to get a Samsung SPH-A460 with Sprint. Unlimited Sprint-to-Sprint was the clincher in the end, although they make you pay $5/month extra for that if you don't get a two-year contract.
I took several pictures through the airplain window of Arazona and New Mexico on the way home. (The pictures aren't online at the moment.) They turned out pretty grey at first, between the window grime and the haze, but using The GIMP to stretch out the value range all the way made for a vivid print. The histogram tool makes it easy to see how much you can adjust to get the full dynamic range.
With regard to printing digital pictures, Shutterfly continues to out-do Snapfish. I ordered from Shutterfly on Wednesday night. The pictures shipped around noon on Thursday and got here today. I ordered from Snapfish on Thursday night and the order just shipped tonight. This is just one datapoint, but Shutterfly has been winning every time.