Have a new HP laptop which measures 15 1/4 across, not quite 10 deep and about 1 1/2 thick. Plan to carry it on occasional long distance trips in the car (probably in the trunk) and perhaps on an airliner. Would like suggestions on what to look for in a bag size and feature-wise. Want adequate protection from expected knocks and bangs, and enough size to accomodate the laptop, power pack, cables and regular size mouse. And not looking for anything overly expensive (of course). Specific questions I have already is should I be looking at a bag advertised as 17" to assure adequate room? Are the less expensive ones, like Kenningston, adequate for protection? Hints and tips welcomed!!