If you try to focus on the people behind the games, I'll bet you'll find, that (most of the time) it's the same companies that make the great stories, and the same companies, that make the really lousy ones. Blizzard is an example - they surely know how to write a storyline! Lucasarts belongs to that group too
k:
On the other hand - ID software/Raven Software ain't exactly known for great storytelling.... :not_ok:
This may of course have something to do with the genres the different companies design their games in....
/Raasted