I have very limited empirical data for this one: A finger dab of myself, the 1998 cast of Saturday Night Live and a handful of Young Republicans at a recent Tea party convention.
Still, this has lead me to the following solid conclusions. Taste does vary from person to person and even greatly within the same person from day to day. This spectrum of semen taste isn't gum balls to lasagna, but it does differ in terms of salty or sweet, bitter or tangy and the like. Diet plays a huge role in taste. Some guys will specifically eat certain foods or avoid caffeine, etc to manipulate their semen taste.
Cinnamon, fruit, celery are said to make the goo sweeter.
Caffeine makes it bitter.
Red meat - salty.
Is this true? I don't know. My sense is that we are talking shades of taste change. Nothing works that much. It's not like if you eat 22 apples or down a bottle of Heinz Ketchup your spew will taste like Watermelon Jolly Ranchers. My further sense is even if you drink three gallons of water or avoid meat, dairy and coffee altogether your jizz will still taste like ...jizz.
The quality of the cocktail comes from your connection to the vessel not its actual content. In other words, while women will say Oh Jason tasted great, or Bobby was one salty fella, at the end of the day, nobody's semen is going to give Snapple or Odwalla a run for their money.