I cannot comment on the lens, but I would like to add a personal experience with the camera body.
About 6 months ago, I was tossing betwen buying a D90, a K-7 or a K-x. I tested all 3 cameras. Both D90 and K-7 cameras were about equally priced then and both are excellent cameras. They have nice image quality, and very good viewfinders for example. The K-7 had a slight edge over the D90 and K-x with the WR, while the K-x viewfinder was disappointing compared to the D90 and K-7.
At the end, the size, weight and shear bulk of the D90 detracted me, and I chose the K-7. I also wanted some solid continuous shooting performances.
Simply the compactness of the Pentax dSLRs is a major advantage in my opinion over the D90. Other might think differently..
But you cannot get it wrong with the D90, the K-7 or the K-x.