The most important is your own comfortability of taking out the camera.
A suitable camera bag will be padded around, thus it should be alright unless your bag is crushed. For mine, I will put it heads down, LCD facing opening of bag cos mine is top-open, when I open my bag, I juz grap it , remove the cover and start snapping.
Fyi - I'm using the Crumpler 5 Million
Cheers.