We prefer to feed raw... http://www.amazon.com/Pitcairns-Complete-Guide-Natural-He... ... but since moving too far away from our butcher have been priced out most of the time (just can't afford wetnoses, or any of the other premade raw dog food)... so now we "rotate". He get's part raw, part Prarie Dry, and part Trader Joes wet.
When we lived close to a butcher it cost less that $20 a month to feed him, now it's closer to $50, and it's still not all raw. 100% premade raw, would cost us around $150-$200 a month. Not happening.
My family has been feeding our animals raw food forever. With pretty standard results. Cats live until their late teens (18-23, although they are indoor/outdoor cats) and dogs live until their early to mid twenties. Rarely do any have health problems... and when the do... they tend to all come at once, a few months before their deaths. Raw food also nixes bad breath. Which I really, really miss. The no "dog breath" thing.
It wasn't until the depression that people started feeding their dogs corn and wheat products. In fact, science diet brand was invented during the fallout from the depression when people couldn't afford to feed their pets real food any more. Their website even talks about it in a glowing way (which in a way, I suppose it is), but finding the least expensive "filler" food that would keep an animal alive... well... I can see why you'd be proud of it in the depression, but not 100 years later when your formula is essentially the same. It's like spam and vitamins will keep you alive, but they won't keep you healthy in the long term, although it will in the short term.
But yeah... find the brands that consist of ingredients that keep grains and veggies at the very BOTTOM of the list. So ones that look like: Beef, Beef Liver, Bone meal, Beef byproduct (skin, intestines, tendons, etc... which carnivores need), h20, & THEN fruits and veggies. They hardly need any, although ALL mammals will eat bread (it's predigested, and so almost straight sugar), like bread the veggies and fruits all need to be cooked (aka partially digested) in order for carnivores to be able to digest them, except for blueberries, which, oddly... carnivores all eat raw quite happily, and they're great for urinary tract health. My lab gets into our blueberries BIG time, lipping them straight off the bushes... which delights my son... and annoys ME.