I am using Body Fortress Whey Protein in chocolate flavor. I asked a vegetarian friend of mine what she used (as she had tried many), and it was her recommendation. You can get a 2lb can of it at Wal-mart for about $15.
One scoop is 140 calories and 26g protein, and it tastes pretty good. I would add a bit of your favorite sweetener (splenda, etc.) as it isn't very sweet, although the fruit may be plenty for that.
I have had one about 2 hours before bed the last two nights (in conjunction with a 1100-1400 cal diet), and both mornings the scale finally moved... woke up 1-2 lbs lighter than the morning before. I am sure it's coincidence, but I like it!!
In reading about it, I read studies that say a good amount of protein before bed keeps your metabolism up while you sleep (could be total bunk?). I do know that drinking that made me stay away from the fridge for my normal late-night munchie problems, so that's good enough reason, I guess.