Marishka's smelly gas has cleared up since getting her off of the kitten chow. She wouldn't eat wet food during the time she was eating that, so I would pretty much attribute it to the kitten chow/low quality food.
Usually in looking for a good cat food, I'm looking at good amounts of *named* protein, protein percentage, no/little by-products, and little grain and fillers as possible. Unfortuneatly most grocery store food isn't the best, but cats are sooooo picky, so reading and testing is a lot of the process. At least with Marishka it is : )
This forum has so many good threads on nutrition (I started about half of them...heh), so doing a search on cat food or nutrition will yield a whole lotta stuff to read...that's what I did.
Also, this link helped me sort out what by products were, what to look for, etc. http://cats.about.com/cs/catfood/a/tipsforchoosing.htm
I am a newbie at it myself, so hopefully I've helped a little. It's overwheling at first since it seems to foreign...but it comes : )
And anyone else, please feel free to add/elaborate/ or correct anything I've said...I'm still learning!