These days, commentary tracks are becoming more and more of a tipping point for me between buying or renting a DVD. I rent way more than I buy, but for the movies that I rented once, liked, but didn't totally fall in love with, I straddle the fence about buying later down the line. If I find a gently used copy a movie with a great commentary track for dirt cheap, I'll pick it up, even if the movie is not in my Top 100 favorites. Amazing how far a great commentary track will go for me.
Case in point, Eli Roth's films. Despite initially saying I didn't want to see Hostel or Hostel: Part II, I saw them. As grossed out as I was with certain scenes (and didn't necessarily find them to be great movies), I thought they were good movies overall. What totally sold me were the multiple commentary tracks for each film. Informative and entertaining, I found listening to them to be very worthwhile. Roth's solo commentary tracks for all of his films document how he got into films and filmmaking, thus making a really intriguing, step-by-step audio-biography of his career.
Another example is The Exorcist. The original and "The Version You've Never Seen" still terrify me, and there's a certain scene that is really hard for me to watch (it's during Reagan's final test before they choose to do the exorcism), but I can't deny how amazing William Friedkin's commentary track is on the original theatrical cut. Detailing what's onscreen while sharing lots of fascinating stories behind the making of the film, it's probably one of the best tracks I've ever heard.
Most recently, I decided to purchase the 3-disc Hot Fuzz DVD set simply for the extras not found on the Region 2 disc (and so I could share the movie with friends that don't have Region-free DVD players). While it may seem a little excessive, I couldn't pass up a chance to hear Edgar Wright and Quentin Tarantino talk movies (and quite a few of them -- here's the list). Hearing two guys who like movies in general, from the highly-lauded to the critically-derided to the popcorn-friendly to the forgotten-by-a-mass-audience, is refreshing. I've listened to enough nitpickers in my life as a movie fan, so it's nice to hear these guys be less-discriminating than what I'm used to.
I've rambled enough about commentary tracks before, but I don't think I've ever said why I like them. Well, they're simply a way to get a better understanding of where movies come from. Though I don't aspire to make a movie, I like to hear from people who actually got something made. It's the general, "this is how it got made, what was fun about it, what wasn't fun about it, what I learned, and what I hope to do in the future." Of course, not all commentary tracks are like this. Enough of them start and stop with praising everybody (from the lead actors all the way to grips) as "brilliant" and/or "genius." Plenty simply narrate what's onscreen -- and it's aggravating.
These days, I find myself having a little more free time since I'm not in the thick of writing and editing a book (and am in beginning of the brainstorming stage for the next one). So, when it's time to cook dinner and wait for everything to warm up, there's usually something in the DVD player. This is the life.