I've had heard a lot of good things about Hanoi before visiting there and I can't do anything but agree. It is a really lovely place!
We visited a darling restaurant and coffee shop called The Hanoi Social Club which was a real oasis. It is located in the old town and the building and the interior is also very nice. I tried their veggie burger (maybe the most Vietnamese :) ,and it was really tasty. But if your are only to eat one thing there, give the flour less chocolate cake a try. Just amazing! I'm going to dream about that one for a long time. Unfortunately there was no time to capture it on photo. I just had to eat it at once :)
The Hanoi Social Club is located here: