Just ordered my new backpack: Mountainsmith Retro Bugaboo, I almost bought it before, but it just went on sale with REI.

Its not a huge bag, but is very comfortable and is pretty much the exact dimensions of a slim carry on bag (I like to travel light and never check baggage). Would have rather had a black bag, but I think I will just cut off the labels to make it a bit less conspicuous.

While I have travel on the mind.. some good links: Art of Travel, and Travellite.