players or DMs?
I voted for "epic storyline" as a DM, because those are the types of campaigns I design. But I love to improvise too, so I don't create the whole thing from the outset. I try to start with a general outline, so that PCs can go another direction if they choose.
That said, the possible goal is always hanging in the distance for the first few adventures, and I try to design it with the PCs in mind. For example, in my current campaign there are two dwarves and two worshipers of Selune (Moon goddess in FR). So the goal became a lost city of dwarves who were allied with a splinter sect of Selunites before the place was laid low by "The Coil" and an army of goblins and worgs. It's not railroading... more tailored specifically for the participants.
But I also like to provide an interactive world...the "storyline" is contantly changing based on PC choices, and there are other groups out there who continue to act no matter what the PCs do.
I don't get a chance to play too much, but when I do it's always to have fun embodying a given character in whatever situations I am placed.