@seaotterDefinitely put QM at the top of the list. Tefler isn't too bad either.
Can't really say I've paid attention to the authors, though. I like long-form stories in general, so who writes them isn't nearly as important as the quality of the writing. Some of the authors might write long, but the stories don't connect with me for any of a hundred reasons.
Lazlo certainly gets on the list, too.
Probably the #1 author that comes to mind would be A Strange Geek with his Haven Series. I dearly wish the next book would be completed so I can find out what happens!