"Hills Science Diet" - was the one that kept our cats very healthy, it's a dry biscuit but we used to mix it with some "wet" packages at tea time. It wasn't cheap and we had to buy it at the RSPCA - anyway the best part was " they're s... didn't smell" esp. if we had an accident inside.
I think they've got one for older cats - miss the guys as they all died of old age and since we both work now we decided not to get another one till someone was at home all day.
