In reply to Griz:
Lots of sensible advice above, but at the end of the day (no pun intended!) it really doesn't matter for single day walk-ins to a crag. for convenience I put hardwear, then harness, then helmet (stuffed with what ever fits), lunch/waterproofs and then rope, hanging across the top as often as not!
For longer trips, sleeping bag, thermarest/stove/food and all the other camping bits, hard wear, waterproofs etc and rope. With hat/gloves and lunch on top.
Basically;
Heavy stuff at top, but balance this with commonsense and convienence.
Do you want your wet weather kit at the bottom? (perhaps if its a lovely day). Do you want your lunch squashed? or your rope and climbing kit at the bottom if the route-in involves scrambling? And if its raining do you want to have to empty your sac to find your tent before putting it up?
What ever you choose you'll make it work and learn what works for you. Enjoy making it up as you go along!
Kev