I have to travel a lot and have to carry a bunch of other stuff with me (2 mouses, phone, international phone, ipod+creditcard/barcode sleeve, too many cables, portable wi-fi router, external mobile battery, android device, paperwork, iPad, ethernet cable, power outlet adaptor, external hard drive, flash drive, chargers ,etc, etc) with my back pack (my personal preference isn't to have a roller backpack as I'm fairly young and i like my hershel backpack) Right now i have a 13" MBP, would that 1 pound difference from using the 13" rMBP help? if it does I'm going to go with the 13" rMBP, if not I'm just going to get the 15" rMBP. on a side note, i don't think upgrading from the Air to the Air 2 would help much, but i do think it did get a bit lighter when i changed from my iPad 3 to the Air. or is it placebo? any thoughts?