Pentax makes some great DSLRs imho - great performance, even better price. Accessories aren't as thorough as Nikon or Canon, and high ISO performance is not as good, nor is AF, but for the average person, it's hard to beat them imho. Pentax cameras are packed with features.
More information and reviews on Pentax cameras can be found here:
http://www.dpreview.com/reviews/specs/Pentax/
A detailed review on the Pentax K20D can be found here:
http://www.dpreview.com/reviews/pentaxk20d/
Some of the cons are I'd argue with - not everyone needs 20,000 fps (exaggeration, but you get what I mean), nor super duper high ISOs, nor super fast AF. Live view is still gimmicky imho, and semi useless even in the best of brands. As to WB (white balance), Canon's WB is awful, Nikon's is very good. Sony, I wouldn't touch with a barge pole. A very large barge pole. Make it a 250 parsec barge pole. Did I mention that I dislike Sony?
What does he primarily shoot? People? Landscape? Nature? Sports? General shooting? Does he intend to become more involved in photography? Does he require specialisted lenses (like Canon's excellent MPE-65 1-5x macro lens)? Has the megapixel bug blinded him? More is not necessarily better. There's an old UNIX saying:
less is more
it's very true imho.
Dave