I think I use backspace about half the time and cmd-left (osx) the other half. I quite like the cmd-left/right because of the symmetry; as far as I know, there is no backspace equivalent for forward.

What's still really annoying is that cmd-back doesn't work if a text input is focussed, so navigating back through several pages becomes a game of repeated cmd-left, interspersed with left clicks on a 'non-active' part of the page, or a series of TABs to leave all inputs.