Tulip's last post just reminded me of a couple favorite smoothies -- some are variations on a theme just for variety:

almond milk + banana + whey protein powder (you can also add slivered almonds for texture if you're using a blender, and when I'm feeling adventurous I'll toss in a tsp of powdered greens)

almond or cow's milk + whey powder + ovaltine

1/2 an avocado + 1 shot espresso + 1-2 T. sweetened condensed milk + ice (you can add a bit of milk to this one if it's too thick)

I'm told the whey powder is a good post-workout protein source. It fills me up, so maybe there's something to it.