From what I gather most people use a Flicker account for hosting pictures but figure I would ask everyone's experince of other sites if they have some. I personally use photobucket and have not really had any issues other than when they changed the site layout made a few days of...."where did that folder go????" comments. After I got used to it no problems really, but I have not tried to sell pictures or upload full resolution pictures either.
I seen a few people use smugmug and a few other sites, I can't think of the name of for the moment, if they wanted to be able to sell pictures online.
Guess the two big questions would be if you were going to sell photo's online who would you use and why, then if you just wanted to post pictures who do you use and why. Then is there something you really wish the site you are using did differently?