Grand Prix Legends.
I am serious. This game is 10 years old but with all the updates it's still unsurpassed. It's unbelievable how good the graphics compare to newer games:
You can get the Grand Prix Legends 2004 Demo for free from here:
http://www.bhmotorsports.com/download/6404
More information in this thread about GPL, TrackIR, TripleHead, etc.
http://forum.racesimcentral.com/show...ght=triplehead
http://www.simhq.com/_technology/technology_065j.html