SODA
Bottle over can & fountain. I don't taste the aluminum in soda cans the way I do in beer cans. Fountain is great, but too often the mix isn't correct or the carbonation is soft. If I knew it was going to be right, I'd choose fountain first. But, if I walk into a place, untasted, it would be bottle, can, fountain.
BEER
Tap
Bottle
Can - definitely a distant 3rd.