You should take the ferry to Staten island if you've got good weather days for water. I've never done that circle line but it looks fantastic. I remember when I went up the WTC, stepping out onto that roof I was unable to move my foot forward for several seconds because it was totally counter intuitive to personal safety.. SO HIGH UP. CLOUDS. eek.. but I did suck it up of course. The tallest building here is all glass on the observation and you can pay some unseemly sum to step out onto glass as well but I skip that part. Don't forget to eat a pretzel. Do they still sell knishes on the street?