Wanted to say thanks to all for this post. Last week, my NXT 2.0 brick popped and started smoking after I put fresh batteries in it. I found this post, contacted LEGO customer service using their online form, and got a call on Monday the 19th (a holiday in the US) that they had already prepared a new brick($170) for shipment and would be sending along a prepaid envelope that I could use to return my damaged brick. They didn't ask for any proof of purchase at all. They just called to let me know they were concerned about my experience, that LEGO engineers would look at the brick and that I a new one was on the way. I got a shipping confirmation from LEGO for my brick this morning. Honestly, I can't remember a better experience with customer service at any company.
Anyway, thanks again. I had planned to take it apart and attempt a repair. While that would have been fun, I'm happy to just have a new one! :-)