A good site for you to read is:
http://www.catinfo.org/
It gives some very good information on the proper nutrition for a cat. IF you can afford to then yes, please feed the best canned grain free foods you can. Wellness, Nature's Variety, Eagle Pack, etc. If you are on a budget as many of us are these days then the
pate style cans of Fancy Feast and Friskies are not bad. Not by any means as good as the more costly foods but they will get the job done and are much better than feeding dry.