++. Preferably the bench....I've always found the car thing a little weird for some reason. Seems antisocial.
I used to do this all the time for my last job...it definitely felt odd at points, especially when somebody walks by and I'm sitting there pigging out on a sandwich.
That said, I really didn't care at that job...I hated it so much that I gladly accepted looking like a doofus over sitting around in the company break room.
To the OP, I second the other suggestions about sitting outside, especially in the nicer weather. At worst, all you really need is a ledge.
I can't remember the last job I worked that didn't, probably some grocery job in high school. And mind you, I work in IT, the abused stepchild of corporate professions.