Although XSane is a great application, I think its interface is not for human beings... Gnome Scan is simpler because it has few options but there are enough for "the rest of us" (people who just want to scan their fotos and save as png, jpg or pdf without no complicated configuration such as brightness, color profiles and so on). So I think Gnome Scan should be the default scanning application in Ubuntu instead of XSane.

Gnome Scan website: http://www.gnome.org/projects/gnome-scan/