I own the k-r and for the price it's a great camera, one of the best entry-level DSLR'S on the market.
The X90 is simply a toy compared to it. Lots of zoom seems enticing but you lose out so much on IQ and you can forget about low-light photography.
Get the k-r with the DA-L 55-300mm kit lens; optically it's much better than the 50-200mm kit lens and obviously you have more reach for wildlife. A 50% crop (eq. 450mm zoom) on the k-r will still be better IQ than the X90 at the long end. Buy a Sigma for the wider angle stuff, maybe a 17-70mm. Eventually you can upgrade your zoom to something really powerful like a Sigma 150-500mm when you've saved up loads more money :)
another alternative if you were really set on getting a superzoom would be the Panasonic FZ-150, probably the best in that field, however, buying a DSLR is something you can really build on.
