The short version: 8-core CPU, 8GB GDDR5, DualShock 4 w/ headset jack and integrated touchpad, improved analog sticks, improved rumble, no PS3 compatibility, continued cross-play with Vita, streaming services that work more like Netflix Instant, allowing you to play digital games as you download them or use the Gaikai app to play stuff immediately, continued use of Blu-ray, due out "in time for Christmas" and... yeah. No word on price, but I'd bet $400-500 is accurate.
Basically, I'm stoked as fuck and want one now. All I was really after was an upgraded PS4, no bullshit forced on me, physical media, and the hardware is a massive jump ahead of what's out now, and easier for developers to work on.
My prediction? PS2 2.0 - shit just got real.