Image shack if im just say hosting a render i need done or a requested tag, but photobucket is better for longer and more user friendly hosting. pbftw~!
Photobucket is way better, because if you use ImageShack you have to re-host them over and over again, unlike Photobucket where you have the gallery type thing... -.-
well... for large crap i use imageshack.. for my sigs i use pb ... usually i just use my own hosting thoo