"BTW, I only have REI and EMS, close to me. It seems REI is an ok place but not sure about Eastern Mountain Sports."

I'm not familiar with EMS, but if you're aiming to be a light or even ultra-light weight backpacker, take care when visiting a place like REI, and in particular, I think it's helpful if a person is conscious of the psychological term anchoring.

I've seen this happen to myself and to others. You go into REI and you see their range of packs and associated weights, and the range that they offer becomes established in your mind as what's "normal". So their lightweight packs seem like a pretty good deal. Then later on the trail you find people with significantly lighter packs that do the job just fine.

REI might do a better job these days of offering somewhat lightweight packs (?), but what I'm suggesting is to not let the set of store offerings establish what's "normal" for you. Look at places like www.gossamergear.com and www.ula-equipment.com/ to get a sense for what a lightweight pack should reasonably weigh.

I suggest that strategy for gear in general, but especially for the big three items. REI is in many ways a great way to shop (if you can afford it ...), I'm not saying that an lightweight backpacker can't buy gear there, but FWIW I didn't end up buying any of the major (larger, heavier) items there (nor did I regret going elsewhere).
Brian Lewis