Scott Hanselman blogged about "14 icons that the younger generation hasn't seen to understand," like Save being a floppy disk.
I did live through the floppy era, and I find that the symbol itself seems to carry the meaning of save, although I don't even think about the connection to floppy drives. It's almost a standard in software, it's quite commonly used to denote save.
Is there a more "up to date" icon that carries the same connotations and enjoys at least some portion of wide usage?