While I love ALMS, other endurance races and F1, for my money the best isn't a single race, it's a series.
WRX has got to have the best drivers in the world. It has cutting edge tech in the cars, constantly changing courses and course conditions. It's run regardless of the weather.
But, if I had to choose just a single race that's the best. It's got to me GP Monaco, just the shear spectacle of it, the machines, the drivers, the crowds.
If I had to pick a series and timeframe, it would be CART in the early to mid 90s and F1 in the 90s through early 2000s.
Being an owner of two motercycles im obliged to go with motoGP