I have never personally used it, but I hear the Tecomante (sp?) lab lab mix is a good one... The main thing you need to decide next is when you want that food plot to be most effective, the warm season crops are very different from the cold weather ones. Here is a link that might be of some help...
http://ckwri.tamuk.edu/fileadmin/user_upload/docs/bulletins/bulletin3.pdf