I haven't found a discussion thread for the followig thread "R3 Card for the Nook Tablet [Root, Rom and Recovery] by Albert Wertz".
Therefore, I post my experience in this thread.
Everything worked as it was described by Albert Wertz in his video.
I just had one problem with the first CM7 image I was using. I then got the latest CM7 image from this thread http://forum.xda-developers.com/show....php?t=1481826
and created a new sdcard. I was not able to just replace the image in the existing card. For some reasons I had to format the old one and flash the image once again.
When I first tried the rooted stock rom, my nook did not boot directly after flashing the rom. I then removed the sdcard and did a hard reset (hold the power button for n seconds). Then my nook booted nicely.
Now, I explore and enjoy CM7. I mainly use it for reading, video and video podcasts. These all works fine for now.
A big thank you to all the developers involved in hacking the nook tablet!