I pre-ordered a Touch after I spent some time intentionally touching my K3 screen and realized that fingerprints really don't show up unless you hold so light glares right into your eyes (which makes it hard to read without fingerprints anyway).
I still considered the K4 Non-Touch, but I'd only be saving $20 (when comparing Special Offers models) and I'd lose the new X-Ray feature:
http://www.youtube.com/watch?v=vUi77I_CXOQ