The nice guys finished first this week, with the squeaky-clean teens of High School Musical 3: Senior Year taking the top spot at the box office with $15.04 million, ahead of a string of R-rated options. The No. 2-4 spots were a tight race, and could change by the time official numbers come out later today, but estimates have Kevin Smith's raunchy, MPAA-baiting comedy Zack And Miri Make A Porno bowing in at No. 2 with $10. 68 million. Saw V held up okay in its second week, bumping down one spot to No. 3 with $10.11 million, while Changeling, which opened in a handful of theaters last week, made its wide-release debut at No. 4 with $9.41 million (and the highest per-screen average in the top 10 by a fairly wide margin).