You forgot PS1. Edit: PS1 is owned by MOMA, if I'm not mistaken, so maybe you didn't forget. But still, the feel is totally different, and it's pretty cool to have to go the middle of nowhere Queens to find a great museum.
PS1 doesn't really have much up at the moment, but Nikolai, if you're here when the NY Art Book Fair is happening, that's the only art thing you really need to do. It takes place at PS1. Keep a whole day free for it. It is the art event each year. http://nyartbookfair.com/ Other than that, screw the Koonsy Whitney right now, MoMA's inbetween some better shows... but actually the New Museum has a surprisingly good show on right now though.
The Art Book Fair looks fantastic, and since I'm arriving on the 27th, there's every chance I can make a visit. Thanks a lot, romkeh.