Wow, this is such a great topic, and something I've been debating for months now. Even tho I'm working digital - which presents other problems, trying to get a watercolor look - I've been totally struggling with line/no line, black line, color line, etc.
What I seem to like best are illustrations that use line sparingly, or all scratchy and loose. I've never worked like that, so I'm fighting the urge to fall back on solid black outlines. Doing master studies seems to help, so I've been doing some in an attempt to loosen up.
I realize lately that I often thought I was doing it wrong if it seemed to easy. Sort of like what you said, @bradyblack and @demotlj , thinking the way you were working wasn't artsy enough or something. I think it's because I see myself as such a terrible amateur that if something comes easily, I assume it must be bad. I'm trying to let go of that and just make something, experiment and see what happens without judging if I'm struggling enough.