I was originally using an S-10 and all my clients liked that truck.
Unfortunately it got the same gas mileage as my current F-150 and I needed to upgrade to a shade bit heavier truck.
If we expand enough to where I need a dedicated gopher/estimating vehicle then it will probably be a small truck of some sort again with the most efficient engine possible.
I'd love to use a car, but then it's just a car and doesn't do much else.
I'm also seriously thinking about converting my vehicles over to natural gas, or propane to help keep costs down.
It's a conundrum none-the-less.