As close as you can to the pilots because they will doing the best not to kill themselves!!!
Thing is, most people who sit in the emerg. exit rows ONLY do it for the legroom and when the hosties come and ask them if they are fine with operating it, you always get "yes yes its ok". Reality is that a lot [not all, but id say the majority] would freak out and not have a clue what to do- or open it into a blazing fireball thats only on one side.......
Rule #1 - save yourself because if nobody does as such, there's nobody to help anyone else!