http://allyoucanupload.webshots.com/

I found this nice site the other day, it seems faster than imageshack, plus anyone can upload multiple files without the need for registration.

Also your upload history is shown at the bottom of the screen, making it easy to find the url for a previous upload. They accept any size of image as long as it gif or jpeg and there are no time limits.

Bye bye imageshack!

Stable though? Some of these sites dissappear or go pay only, or something tupid.

I use the imageshack shell plugin, you right click your images (1 or more) and then click upload to image shack and it bulk uploads them.