I have always enjoyed 'Le Mans' with Steve McQueen. Had it on VHS and now on DVD, and this reminds me that I have not watched it in a long time!
In my opinion there are few movies about racing that capture it in a realistic way, and the movie is free of "Hollywood embellishments'.
Le Mans is the only one I bought. I thoroughly enjoyed Rush - saw it twice at the theater - the real events happened during my youth and when I was an avid F1 fan. I will add the Bluray to my collection when it comes out.