There's a nice promo video about the Airbus 320 and its fly-by-wire features over at

www.airsidetv.com

which shows how it can take off on a single engine with no problem. In the video they take off and then, right in the middle of takeoff, completely shut down an engine and never touch the control sticks. The plane doesn't budge one bit. It does everything automatically to keep the plane flying at the exact same attitude and speed.

Of course, you would then turn around and land the thing since you just lost an engine, but it's nice to know that margin for error is there.

I always feel safer when riding an Airbus after watching that video demonstration.