I finally scrounged for $10.50 and ordered the DVD of Dr. Horrible's Sing-Along Blog on Amazon. I came home yesterday to find that it had arrived on my doorstep!
More than re-watching the film, I look forward to viewing it with Commentary the Musical featured on the DVD. I've heard good things about it and if you don't yet have the DVD, much of the Commentary is available on YouTube. Whedon has said that it actually took twice as long to make it than the 45 minute piece itself!