It's not really possible to say what is the 'best' brand of food as what suits one dog may not suit another and there are other diets to consider as well such as home cooked or raw/BARF feeding. Good quality wet foods are Nature Diet, Nature's Menu, Nature's Harvest and James Wellbeloved pouches. Some good quality dry foods are Barking Heads, Healthy Paws, Arden Grange, Burns, James Wellbeloved, Robbie's and Orijen. Low quality foods that are not recommended are Pedigree, Bakers etc. and there are others of middling quality which are somewhere in between.
Personally I feed Healthy Paws and I think it's the best dry food I've found, it's all natural, uses very high quality ingredients, doesn't contain any wheat, dairy or cheap fillers such as beet pulp and the dogs love it so I think it's excellent but others may not agree, it's really horses for courses.
If you have a read though this board you'll find lots of threads on various foods and see what people recommend or don't recommend.
