I finally got the special edition for Aliens, and that one is pretty extensive. They really go through everything from pre-production to post, and it was great seeing interviews with the cast, including Carrie Henn (Newt), and even her brother, who played Newt's brother in the film, but his footage was cut from the theatrical release. Seeing how all the weapons were made was fantastic, and of course all the work that went into the Queen Alien, because even now that I know how they did it, I still look at the film, and I'm still amazed that they actually pulled it off. Same with the Power Loader.
The Frighteners is another great DVD for the special features.
The DVD for the first Blade is still one of my favorites. For a one-disc deal, it was pretty extensive in showing how they developed the look and story of the film. You have to figure, now it's a situation where all the features go on a separate disc, and sometimes, it's still pretty barebones. When DVDs were just starting out, Blade was the top seller for a good long while, and with good reason.