Upload & Sell: Off
Eh. This is a tough question.
$100 P&S vs. Old School Film: Convenient, but not really an improvement. Good luck with ISO 200.
+$400 for a m4/3 camera - gets you access to a bunch of lenses, fast primes, and good until ISO800. much better shutter response. Nice value there!
+$500 to an Olympus OM-D - gets you some more dynamic range... eh, not at double the price.
+$0 to a D7000 - cutting edge dynamic range, healthy resolution, good FPS, good shutter response, decent AF. Nice value there!
+$1000 to a D600 - access to full frame lenses. same DR. a step up in High-ISO. Sell your firstborn child to upgrade your entire lens lineup to FX, get a new tripod to handle the weight, a new bag to hold your volumous gear, pay your chiropractor for your broken back. pay your psychologist to smooth to smooth out your financially strained marriage. Value? Eh. Ok I guess.
+$1000 to a D800 - more MP. 'Pro' functions. Buy new glasses because you messed up your eyes pixel peeping. Value? PRICELESS.
In all honestly, most people don't need a D800. It's a luxury item.