I keep doing that too, but i find that the more expensive ones tend to really dry my hair out, like trevor sorbie did, id never use them again. I find tresemme works really well, it seems the obvious choice, but its eally good, especially the intensive conditioner. Superdrugs are doing buy one get one free at the mo too.
Head and shoulders are also good for my hair, i like the one for dry hair and the one thats for soothing a dry scalp-its so nice. I also sometimes use palmers hair shampoo. I haven't tried the body shop stuff but will be soon, and hair conditioners by lush (in the tubs) ae natural and really good