What is the best kind of cat food?



My cat just had a massive operation on his digestive system and I want to know what is the best kind of cat food, he usually has Whiskas and I know there are better ones but he has always liked it. He cant really have gravy foods because they dont agree with him and I have heard they arent as good anyways. Could you please tell me what the best brand of cat food is that I can get access to in Australia? And what about meats and meat preparation if I want to make him some myself? What about biscuits?