I don't particularly like the "back" button, because depending on the browser, it may not provide a good visual indication of just where I am going back to, or what happens with intermediate POSTs. (Yay for Mozilla which seems to keep the contents of my textareas infinitely better than IE)
I would prefer a server supported backup mechanism. If the browser is stateless, it's not clear to me it knows how to backup in any way much better than a cat with a paper cup over its face does.
