The best seats at the American Family Insurance Amphitheater are undoubtedly the ones under cover, sections 1 through 21, but the premier area, sections 1, 2 and 3 will offer unrivaled views as you are practically on the stage. The more distant lawn seats are no longer under the canopy and depending on the band performing you may be required to stand to see!
As you can see from the lawn view, it pays to get tickets for as close as possible, though the bowl nature of the pavilion does mean that everyone can the bands on stage!