I do soy protein isolate smoothies, and that's...well...only slightly pricier than whey. I remember reading that egg protein's the most absorbable, but I likes me soy.
I dunno if veganism makes you more clearheaded (if so I can use all the help I can get on that one)...but it does improve your sense of smell.
Then what's your reason for choosing veganism over vegetarian?:shrug: