We had a great stay at Octavo Guesthouse, the owners we very helpful regarding the arrival (we arrive around 1am).
The location is very good, 10 minutes walk to reykjavik city centre.
The room was great, very well decorated and comfortable, with a small kitchen, the only "bad" thing was that the bathroom wasn't inside the bedroom, but still not a problem at all.
The room view was for the building backyard which was very cosy.
Like everywhere in iceland the offer wireless internet.