Ask HN: What is the best way to record tech presentations?

My startup is going to be producing and organizing a lot of tech presentations over the next year, and I wanted to get a robust, convenient solution in place for high quality recording of video and audio.

After doing some research, it looks like a video framegrabber, a video camera, and a few wireless mics is really the way to go. There is a company that sells an all-in-one box that purported does what I need, but I have heard some negative reviews of their other framegrabber devices (specifically the VGA2USB box): http://www.epiphan.com/products/recording/lecture-recorder-x2/

I thought that given how many tech presentations and conferences happen every year, this must surely be a solved problem with someone having documented some best practices. Sadly, this is not the case, so I am seeking the wisdom of the crowd here at HackerNews.

What kinds of setups have you seen for doing high-quality recording of technical presentations? What is the easiest to operate? What setups are the least error-prone?