We have several kinds of black ground beetles, which are usually moving rapidly and thus defying the photographer...it's amazing how fast they can move on those short little legs. But this large one was just sitting there on the sidewalk from the carport the other night. I like the elegant shape of it--it's a male (the large "jaws") and the thin blue line at the base of the wing-case (the elytra.) The blue doesn't really show here (on my laptop monitor) but it was there. I think this beetle is in the genus Pasimachus. They're insect predators, going after (among other things) caterpillars.
The one on the right is a type of June beetle, but much larger than most of ours, and a plainer brown (not so red-brown), but with spots. It's about an inch long, and was on the kitchen storm door this morning. I think it's in the genus Phyllophaga. (Quick correction--the word back from the entomologist list is that it's a Grapevine Beetle, Pelidnota punctata.)
Beetles, according to my insect books, are the most diverse organisms on the planet--one in five of all living things (plants included) is a beetle. There are over 24,000 species of beetles in North America north of Mexico.