Asherons Call: Loremaster Question of the Week

This question probably doesn't qualify as a proper Loremaster-type question (it doesn't even apply specifically to AC), but it's been rattling around in my head for the last few days and I think it's an important one:

Just how important is lore and other story material to a game (any game, not just AC)? Is the storyline an important part of a game? Is it something that's somewhat important but still secondary to things like gameplay? Or is it, as (I believe) dugfromthearth once put it, simply a reason why something sucks, and ultimately unimportant?