I'm a borderline young person, so I guess I can comment. Good aesthetics and good content seem circular. If a site looks good, I'm probably more inclined to look around, bookmark it, or contribute to the content. Conversely, if the content's good on its own, that might give it the popularity that spurs some visual improvement. A lot of popular sites weren't particularly pretty when they launched/grew (take Facebook), and some still aren't. But if it's a user-driven site, people might be less inclined to contribute information or come back in the first place if its ugly. So, I generally try not to separate the two in my own work. Form and function follow each other around.