Magic Find Consumables Guide
Magic Find in Guild Wars 2 increases the chances of you finding rare or valuable goods from drops. It works on all drops whether it be from a mob, boss or a chest. Based on reports from many different players (although no information from any developers yet as of 9/30/12) Magic Find also works on gathering nodes. For example if you have high Magic Find when Logging from a tree you will have a higher chance to get a Hidden Trove.
Or if you have high Magic Find and you're Mining some Ore you have a much better chance of finding one of the green, blue or rare gemstones that can be found in the mines.
List of Magic Find Consumable Food Products
Blueberry Tart - Req level 5
Clam Cake - Req 25
Yam Fritter - Req 30
Orange Coconut Bar - Req 50
Raspberry Peach Bar - Req 70
Omnomberry Bar - Req 80
Cup of Lotus Fries - Req 80
There are a few more types of food you can buy that have Magic Find but these are the most "solid" ones so to speak that you can choose all the way up to 80. Other Magic Find food sometimes only works while you're under the effects of a Boon. While it may be more Magic Find than the regular foods you come across (Omnomberry Bar is 30% Magic Find and the Boon version of it is Chocolate Omnomberry Cream which is 40% Magic Find) for a lot of classes it is difficult to keep a boon on yourself at all times.
For this reason I only recommend you buy the foods mentioned above. Also the 40% extra gold from monsters on the Omnomberry Bar probably helps out more than the 10% more Magic Find from the Chocolate Omnomberry Cream in the long run if you are killing mobs that have a chance to drop coin (which I am fairly certain all mobs have a chance).
Video of all the Magic Find Foods