everywhere. i like turn 6 cause you are really close to the track. but you HAVE to spend time at the corkscrew. get there early and nab a spot just in front of the bridge, down near the bottom of the hill. you can see the whole corkscrew from there. also, the grandstands at turn 4 are nice because there is a jumbo-tron right across the track, so when the action isnt in front of you you can watch the tv feed.
i sit grandstand turn 11 for the race, and for practice and qualifying i walk around. get the pit pass, youll kick your own ass if you dont, the top of the corkscrew is a hike, but the top is a great view of the coolest turn ever. have fun bro.