If you're going to Cincy (which I highly recommend), go to the day sessions on Tuesday or Wednesday. Nights are fun, but there are so many more matches to choose from during the day. You'll get a reserved seat that's some distance away from the court in the main stadium, but you'll get access to courtside seats on every other court (as long as you claim a spot early enough). I was about 6 feet away from Federer, Ferrero, El Ayanoui on the grandstand court last year. Awesome, and totally worth the price.
Feel free to ask more questions.