Actually, you can get to a terminal without going to developer mode: http://calamitylane.com/articles/programming/chrome-os-on-th...

...but that's pretty sweet. :)

That "crosh" shell is actually extremely limited, only allowing a handful of basic commands. (ssh, ping, traceroute, top, a couple of other misc utilities -- but no text editor.)

You still need to enable developer mode to get to a "traditional" linux shell: http://www.chromium.org/poking-around-your-chrome-os-device