I'm having almost exactly the same problem.
Bit of background:
I have NOT done any rooting/bootloading etc with my Nexus 7. It's pretty much out-of-box except for a bunch of apps and videos I'd downloaded.
I gave it a full charge when I received it (Wednesday). The battery still hadn't fully drained by last night (Thursday) so I left an HD video running to drain it fully (Indie Game: The movie, in case anyone was curious >_<). After a while, I left it turned off and plugged it in to charge overnight.
This morning (Friday) I turned it on, and now it's stuck in an endless boot load. Mine gets further than ngorr's, in that it boots all the way to the lock screen but literally 4/5 seconds later it crashes (I can actually unlock the screen and move the desktop panes very briefly before it freezes and then reboots).
I can break the reboot cycle by going into bootloader (power + vol up + vol down) and use that to "Power Off" the device. As like ngorr's device though, if I try to boot into recovery mode it hangs on the "Google" logo indefinitely and I have to perform a hard reset, at which point it goes back into the endless reboot cycle.
Any suggestions? Again, I haven't attempted to load any custom roms, or root the device etc. All I can think of is that, while I was playing the video to drain the battery a firmware upgrade may have tried to install, but halfway through the battery died? But if that was the case, I doubt it'd get to the lockscreen/desktop pane.
HALP! >_<
P.s. sorry for potentially unecessary amount of detail.
[EDIT: Called Google on 0800 328 6081, tech support couldn't help me so they're sending a replacement. Not a satisfactory solution in my opinion, having had to wait a week longer than people who didn't pre-order etc etc]