Pepsi for sure, I add it to my rum!
Coke doesn't do double blind taste studies any more. There has been extensive research done, and during taste tests, pepsi wins 60% of the time.
However, coke sells more product, and the research suggests that it is because of the name coke, coca-cola - that makes it more popular at the supermarket. Kind of like how everyone calls tissue, kleen-ex - and now it is the top brand.
Rye and coke is the name, not Rye and pepsi. Some coke fans are brainwashed by the name thing, and the advertisments. Coke has spent money to keep the results of those tests from being widely published.