The best!
The place to stay in hanoi if you want to meet people and get some sound advice on the city.
Website is www.hanoibackpackershostel.com
PLEAE NOTE THAT A LOT OF CABS HAVE A DEAL WITH THE 'HANOI BACKPACKERS HOTEL' AND TAKE PEOPLE HERE- THIS IS NOT THE HOSTEL, IF YOURE TAKEN HERE, LEAVE AND FIND YOUR WAY TO THE HOSTEL.
My brother worked at this hostel which is why i was in hanoi, visiting him , i am not being bias, its really is a good hostel. you may pay slightly more ($4.5 for a dorm) than some guesthouses, but the people you will meet, the information they can provide is worth it and makes it good value for money. 2 aussie guys Max and Mike run it, theyre really friendly and know everyone by name. they know what people want from a hostel. theres also veitnamese staff working there so its not totally western.