Well, young men are spicier because of the testosterone levels... gang members because they're violent and have seen more, done more. They're also a little smoky, a little smooth...

Rich young white girls are a bit like per seco, but less bubbly... more bubbly as you get closer to middle class...

Depends on how you catch them, too. Fear will give the blood a metallic tinge, and if you put them to sleep the flavours mellow... those who enjoy the experience are sweeter, I'm told, but blood slaves smell so... clean. Antiseptic, almost.