Just saw Senna in the theater today and I highly recommend it. It's chock full of great race footage, behind the scenes stuff, and LOTS of tension between Prost and Senna. Just go see it. It's playing now at the Angelika in Dallas (Mockingbird Station).
As a side note, I was shocked to find the theater PACKED for a 3:30 show today. When we got out, there was already a long line of people waiting to get into the next show. And they didn't look like your average car dorks, either. Lots of chicks, lots of old folks, lots of kids, lots of regular people not wearing McLaren shirts and Lotus jackets.