Ill be the first to say that RAW, 16-bit and none destructive editing is awesome!
But Ill also say that; It isnt ALWAYS necessary.
I hang at alot of these gear-freak forums, where people worry more about the technical stuff, and take about 100 images on their D300 before they feel they need a d3 since the d300 obviously isnt quite good enough for their needs.
These are the same people that are VERY entusiasthic about none destructive editing, and really engage in all discussions on technicalities.
But at some point you just gotta ask yourself when enough is enough.
I do quite a bit of work where speed trumphs none destructivity, and I find myself working on JPEGs, and saving back to JPEG, and actually resizing before starting the editing. Its fast. Very fast.
Because sometimes you just KNOW that you wont need this image in 50x60CM, and sure as hell dont need a 16bit PSD file with all the layers set up completely nonedestructive =D
(ofcourse the story is quite different on bigger things; like composites etc, there I work with a completely none destructive workflow, with smartobjects, 16bit and everything.)
Anyway; heres some more on this theme from Matt Kloskowski from Lightroom killertips, guestblogging at Scott Kelbys blogg:
So I recomend this post for everyone who is perhaps a tad to focused on none destructivity, and a little bit to little focused on just getting the job done =D