Erm, everything? LOL

In no particular order

- Go up the Empire State (don't bother going to the top floor, go to the viewing deck on the 82nd or whatever floor it is) Get loads of cool pics
- Then go up the Rockafella - get more cool pics, this time with the Empire State in them lol
- Boat tour from around 42nd-44th Street West - the BEST way to see Manhatten, and excellent voice-tour guides too
- Walk around Wall Street + the NY Stock Exchange
- Walk from Battery Park all the way to Central Park (ask Erik - I did this! Twice )
- Central Park - just see all of it! Honestly, one of my favorite places in the whole world!
- Ride the subway
- Visit "Three L's Pizza" (315 Broadway) aswell as Ben's Pizza (177 Spring St) - best pizza EVER!
- Meat District around 14th St is quite cool
- As is the South Street docks (under the FDR)
- The Met (art museum)
- American Indian Museum
- And if you fancy it, The Sex Museum lol
- Take a walk into and around China Town
- The WTC site and obviously Ground Zero - very humbling
- Ghostbusters firehouse (14 N. Moore St)
- Take a trip to New Jersey (just across the Hudson) and see Manhattan all lit up at night
- Obviously go to Liberty Island. Go to Ellis Island aswell if you like history stuff...
- Walk across the Brooklyn Bridge. Get a cab back the other way
- Go to Madison Square Garden, then walk over to Grand Central Station.

Personally, I just walk around everywhere - best way to see virtually everything. As you walk around you find more and more stuff to go see/look at/walk round...