door design. i'd recommend the single lid that hinges on the front. i've got the gull wing doors on the ends and they're a pita to get heavy things in/out of.

shallow vs deep. the deep one's hold more stuff, but you'll need some milk crates or rubbermaids to keep stuff from getting all piled up. i had a deep one but traded it to a buddy for a shallow so that i can occasionally slide it back a little and use the stake pockets. the deep one would slide back because it would hit the fender wells.

inside mine are tool box, come-along, 4 way lug, fire ext, chain, tow strap, tarp, football, first aid kit, etc.
underneath the tool box are a couple of shallow rubbermaids. in there are jumper cables, more tools, lots of misc stuff, tire plugs, cables, hooks, shackles,