The Central Hostel is great!
Couldn't be more perfectly located - right next to the cathedral and a Carrefour City and with a lovely vegan café just a few blocks away. The hostel was extremely modern and beautifully designed - with a lot of privacy even in the dorm rooms. The staff is very friendly and the live music in the evening was just the cherry on top! The bathrooms were impeccable and even the stairway is an attraction for itself, should be in Bordeaux tourist guides.
I'd come back any time and highly recommend the hostel!