Dx vs fx and choosing a religion.

I am deciding between the d600 and the d7000/5100/3200. ive generally come around to the school of thought that says for so many uses, there is little difference between the fxs and the dxs.  Sure I like the larger viewfinder On the d600.  But for the differences, I could really spend that difference on lenses particular to my use (sports and landscapes).  The Dx might even have an advantage in that the added reach for sports is far cheaper with the dx.  My big concern with the dx lenses is their limitations with a fx sensor.  You condition yourself to believe that your choosing a religion in selecting a brand and people talk about passing glass down to their kids.  coming to terms with the  dx limitations, I feel like I'm being shortsighted- and only choosing a religion for three years.  Am I being unreasonable to be this concerned about dx lenses?