Can anybody identify this spider for me?

Last night I found a dead spider at the bottom of our stairs, and it was a type that I see all the time in our house – probably 90% of the spiders I see are this kind. So I decided to put my new digital camera to the test and see how well macro mode works. I think they turned out reasonably well, although the flash may have been a mistake. Anyway, so here are three pictures of the dead spider, one ventral, one dorsal, and one next to a quarter for a size comparison:

Dorsal view

Ventral view

Size comparison to US quarter

I thought it might be a woodlouse hunter, which would make sense since we have a huge number of wood lice (aka pillbugs [where I grew up] or roly-polies [where I live now, so that’s what my wife and daughters call them]) in our yard. But the chelicerae on those woodlouse hunters, and particularly the fangs, seem way bigger than the ones on the spiders at my house like this one. Although maybe “my” spiders, including this one, are just hiding their enormous venom-dripping fangs from view…

Anyway, if anybody can help, I’d greatly appreciate it! I’m especially interested in finding out if these things have a painful bite.

Callobius severus