Zodiac is the best movie of 2007 and it's on DVD now.

I have seen All the Presidents Men about 20 times and this procedural/thriller movie was made in a very similar fashion, except the creepiness meter is on about 8 or 9 the whole time. I remember reading about the killer as a kid and after seeing the movie I am sure glad I didn't live in the Bay Area at the time. Lots of great actors, tons of great costumes and visuals, and an excellent soundtrack.

Read about the murders here and the movie here.