It's actually the *ist DL2

, but I guess there is not much difference in the user interface between the DL and K100D/S....

The OP likes his 2.8 lenses, and my DA*16-50 is sharp...That's what I would recommend. BUT, here's the BUT, to get the best of the DA* lenses you have to have the K100D Super, K10D, K20D or K200D (for SDM)...

If you can find one the FA 24-90 is Superb (FA is Pentax's line of film SLR AF lenses). The Sigma DC 17-70 has its fans. I have a Sigma EX 24-70 (EX is Sigma's pro line) which is a really good lens.