Note that there's also the "K100 Super", which is identical to the regular K100 except
- adds support for the ultrasonic ring motors in the ~$1000 DA* lenses (and presumably other upcoming lenses). Lenses still work on older models, just not using the ultrasonic (silent) focus motor.
- adds anti-sensor-dust features, which have been shown to not actually work all that well.
- about $100 more expensive.
It's a really good camera, although it's got some user-interface annoyances common to all entry-level dSLRs. Despite that, though, it can take great pictures.
I'm hoping that Pentax has a more major replacement entry-level camera (K200D?) up its sleeve (as part of the expected announcements at PMA in January), but even then, that's likely to start at $500 for the body, so if cost is an issue, holding out for that hope probably isn't worthwhile.