If you're starting out it's probably best / easiest, to pick at least 1 of each flavour so you can try them all and figure out which flavours you like most. A flavour which I love could be the one flavour you really hate.. I've seen as much now my mum started CD last week lol.. She loves all the shakes I really do not like..
I stick mainly with the chocolate, and chocolate mint both of which I have as a hot drink. In the morning I split my first shake half into a bowl and half into a mug. The part in the bowl I mix with psyllium husks and make it into a sort of porridge. Helps fill me up and keeps you going too. I also have the tetra's when I'm going out at weekends. Good luck hope you enjoy them.