If you can get used K10/20 that would me great intro to DSLR world.
Functionality of that body is just incredible, and good old K10 are still very capable of mind blowing results. If you need better high ISO go for K20.
With that type of body you are getting great ergonomics, 2 dials, great customization, good VF, weather seals, SDM support, SR, selectable AF points, very good battery life.... and you don't have to pay all that much
Personally, I'd pick used K10/20 over anything that Pentax currently offers new (well OK, I'd take 645D if I could but that's another story
). If you'll do, you will not regret...