In reply to PontiusPirate:
Let me just save you the hassle and experimentation I have done over the years.
Hemp - Natural but strong flavour and relatively low protein content. Higher in omega oils, but that's usually not why you're taking it.
Rice - fairly digestible but has the consistency of sand and has a flavour that is hard to cover up.
Pea - the best of all. Mixes well, great texture, cheap, digestible, 80% protein content and has a flavour that tends to take on other things quite well.
I get Pulsin Pea protein in the large bags. It's unflavoured so I can put it into virtually anything (brownies, shakes, even savoury dishes). If you want to flavour it just pour in a bottle of vegan hot chocolate powder. Personally I just use sweetened rice milk and cocoa - and sometimes a banana if I need the extra boost.