Here's my notes from TechEd North America 2010
They are extensive, yes. I tried to make them somewhat interesting to read with humor and such. My boss, who dropped big bucks on the conference and expects me to be able to bill in kind to cover the investment by a factor of ten, really likes the fact that I produced notes of this length. It will be a factor in the decision to send me to more conferences in the future. I'll be sharing the notes with the department as well.
If you get sent to a conference, I'd recommend doing something like this as well, in addition to giving a knowledge share with your colleagues afterwards. Its best to type up your notes ASAP after the class, so that you can decipher what your wrote/typed and make sure it is explained well to someone who wasn't at the class. Include the slide downloads and videos, if provided by the conference.
If you're a manager, I'd set requirements like this in place beforehand and make sure the expectation is that this isn't a vacation, this isn't a free training for the betterment of your career, this is a focused training aimed at improving your ability to work/bill in your intended job role. You're wasting your company's money if you come to costly conferences like TechEd and hang out at the expo all day, or take certification practice exams, or just drink and party on Bourbon Street.