So I ask you FF shooters: what is it that you can do nowadays with you FF that you would no longer be able to do if you downgraded to crop?
Well, no small number of FF shooters would miss the ability to post smug things about how superior FF is on intangible things like dreamy bokeh, color saturation, etc..., whether they could actually pick a FF print out of a police lineup or not.
I think the biggest thing about going FF to crop would be losing 2 or 3 stops of low-noise performance at higher ISO settings, at least when comparing it to the newest FF bodies. That is very valuable stuff.
I think you can get all the blurry background/shallow depth of field most people would really ever want using a crop body by following the basic rules. Bright prime lens shot wide open, shot close to subject, background far away, etc... Frankly, I find the 50 f/1.8 DOF shot on a crop to be too thin sometimes. My wife actively dislikes the look, actually, when we shoot my girls and you see an eye or two in focus, but an ear that is blurry.
Three pages later and nothing has been added. This thread could have stopped with Scotty's response and covered about everything that needs to be covered.