If you are on 8th Avenue, and you see a bakery near 30th St proclaiming to have the "worlds best cheesecake", don't fall for it. It was nice, but I have had better.
A bit further up 8th Avenue (around 33rd/34th, nr MSG) there was a Irish pub/restraunt. In there I had the best steak ever. They should have claimed it was the "worlds best steak" because it was awesome. And the waitress was fit as f**k. I wish I could remember the name of the place so I could recommend it properly. Don't venture too much further up 8th Avenue though, it gets pretty seedy! (Well it did when I went about 5 years ago).
Don't get in a taxi and ask him to take you to 110th St because you want to walk through the park... the driver will look at you like you are crazy (and it would be a stupid thing to do. Trust me.)
Go to the Disney Shop on 5th Avenue. It had a Mr Potato Head pick n mix.