imgur is the best host. it can take up to 1.999mb of any format, uploads nearly instantly, you can click-drag stuff from your folders onto the website to upload, and there are no ads anywhere.
Try Photobucket. It does require registering, though.
it has a bandwidth limit and the website was plastered with ads and a stuffty layout last time i used it in 2008ish
TinyPic and photobucket
tinypic has terrible download speeds and causes broken links
Just attach them to posts. :D
slow as stuff, guests cannot view them, tiny resolution until clicked.