[Yours]

I find that it isn't always just about content. Remember conent isn't your number one thing.

Lets say you have the greatest content in the world, but your staff are all stuckup +++++++s who ban people for no reason, bash people, and all around aren't very nice. People will notice this and not want to sign up/stay. For me I think the best thing to go with would not be at first content but staffing. Make sure you have active staff members who are nice, helpfull, and don't go off the deep end over stupid stuff.
Now you state you don't want to spend a lot of time on this soon to be "big board", but i'm sorry you have to be on the site a considerably large amount of time, or atleast make sure a few staff members are being active around the clock. Without staff, your site is nothing.

Make it a warm environment, make the site look good, both in content, and layout. Never lie about your statistics with the "fake community statistics" mods, and NEVER overcrowd your forums with 10 billion mods. Try to keep it basic. "the more the merrier" is not the case.
I would also suggest not changing too much too often. If you go through 10 different skins every month people will get confused. My suggestion: make a foundation of the site make it how you want it get mods and templates, make sure its all working, before you release it to the public. That way you don't make huge changes throughout your website's life.

For me, simplicity is best.