If you can have fruit, how about some frozen strawberries, blueberries, raspberries, etc for a fruity type shake......If you use the frozen, you can use less ice......Add a little extra vanilla extract for a more vanilla flavor.....
go to wal-mart and get a bag of peanut butter cups or chocolate-mint cups. that makes a great shake. or you can drop a spoonful of peanutbutter in the shake. the peanut butter cups kick ass!