We were advised to look at Lake Tekapo on the way to Mount Cook, great, but the best lake was the one we drove round to get here, Lake Pukaki, fantastic start to a great campsite. A long road to get to the foot of the mountains but well worth it. The campsite is, as most DOC sites are, quite basic, water not to be drunk etc and toilets, well, whatever. If you are self contained these sites are the best to stay on. We actually witnessed an avalanche in the evening which was amazing.
Having done a huge walk to the foot of Mount Cook over swing bridges, rocks, climbing, paddling etc (supposedly one of their easy walks!!!) to see Icebergs etc, it was just great sitting by the mountains with a beer taking in the magnificent scenery. Would really recommend this site to any fellow camper.