Not only all the above are true, but the amount of aftermarket products aplicable to the vehicle is important as well. Sometimes it is best to be able to buy a well thought out and engineered upgrade part (suspension, skids, ect.) than fabricate your own and learn the hard way. I selected my rig based upon the upgradability and the stock performance. Since the stock performance of the vehicle is adequate to get to many i thought i couldn't, stock will do as I save up to upgrade certian aspects of the vehicle. Many rigs as mentioned above are highly capable right off the lot, as you fabricate and upgrade, the capabilities slow increase as well.
However, I disagree with Scotts pos't in regards to DVD players... in fact I have one on my list of wants, due to the inputs and posibilty of a self spotting system. This could also benefit the passengers, old or young, since most units can opperate independantly. For example, you could have an in dash unit displaying your rear view camera, and could be playing a children's DVD in the back with headsets (so you don't end up singing Barney songs all day) and you could still be listening to the radio. Infact, some DVD players have built in GPS, and vehicle monitoring systems, because of this I believe this technology is befitial and has a value to an expediton vehicle... But this is depending upon the set up of the system.