I really appreciated the move up from our old 6 MP (megapixel) Canon 10D to a 21 MP Canon 5D mkII: Not only could I print larger images with respectable resolution, I could also pull finer detail out of an image, or zoom in on and crop down to a relatively small portion of the frame. But of course, this is tiddlywinks compared to really high-end digital camera backs, where 80 MP is defining the new high end. The well-respected Michael Reichmann of Luminous Landscape notes “if you step up from a 24MP or smaller DSLR you'll be stepping into the bizzaro universe, where resolving tiny flecks of mascara on a model's eyelashes from 20 feet away becomes commonplace, and being able to clearly see telephone wires at a distance of 2 miles always amazes.”
Michael had a chance to play with two new 80MP models – the Leaf Aptus 212 (approx. $32,000) and Phase One IQ180 ($43,990) – both of which sport full-frame 645 sensors (60 x 45 mm) compared to the 5D mkII's 35mm full-frame sensor (36 x 24 mm) in addition to their insanely high resolution. I highly recommend you read his Phase One IQ180 and Leaf Aptus II-12 reviews, as well as watch his interview with Leaf's Product Manager Yair Shahar and Phase's U.S. Vice President Kevin Raber (at the same time, sitting on the same couch).
No, I'm not saying you have to go out and buy today. But it's always good to be aware of what's possible.