I had a very good time at the Queen's Hostel. The beds are comfortable and the rooms, while not spacious, are open and airy enough that I always got a good nights rest. The breakfast was good but basic. The hostel also had a consistently relaxed and friendly atmosphere.
The one downside with the hostel would be that it is a 5-10 minute walk away from the closest underground station (White City) but that is a small thing.