Some of you perceptively noticed that I was using nvALT 2.0 in my screencasts. Well that's true, and I've really been enjoying it. It's a great release. Get it here for zero dollars, but seriously consider clicking that donation link on the right side of Brett's site.
I'm also really grateful for the efforts of Zachary (for making and maintaining the core NV release) as well as Christian and David for their work extending NV in the direction of a full-blown Markdown editor.
Update: Use the donation link on this page if you want to contribute to the nvALT project.