I have to admit I'm one of those guilty of hogging overhead space. Since Jan 2000, I've travelled with a wheeled garment bag (size similar to http://www.ebags.com/products/index....%20Cole_63711). It's almost 2x wide, but same height and depth to accomodate overheads on CO and NW planes (except RJ and puddle-hoppers). Only time when I had it checked in was when the ground crew are total sticklers (for example SIN, HKG, MEL, SYD). If I cannot carry extras, I mail it home.

The spouse on the other hand, does not want to carry anything. When we travel together, I almost always have to insist on getting the priority tags to expedite. On a sidenote, anybody notice that priority marked (yellow tag) does not always come ahead of regular bags on most domestic flights???