To try and clarify the mixed answers that are being given here:

Yes, statistically speaking the back is marginally safer than the front or mid-section.

I’ve heard it posited that sitting over the wing spar is a good spot too as it’s one of the strongest parts of the airframe – but, clearly, good luck on the day is the most important factor.

Funnily enough, I always head to the rear on flights without allocated seats – I’m 6′ 4″ so I like emergency exit rows too.

Wasn’t there a study, after Manchester and other crashes involving evacuations, that concluded 7 was the golden number?

ie: the chances of people sitting more than 7 rows away from an emergency exit getting out were the lowest of everyone aboard – makes sense really.