Join Date: May 2012
Location: MCO
Programs: AA, B6, DL, EK, EY, QR, SQ, UA, Amex Plat, Marriott Tit, HHonors Gold
Posts: 12,810
In general, I'd take the 757 over the other two. Positives:
-best chance for upgrade
-roomiest of the three (763 is very cozy as you mentioned)
-boards through L2 in most cases (best shot at PDB)
-not as noisy as the 737
Only exception would be if the 763 was an international version, in that case that would definitely be the way to go.