Have you seen The Social Network? :)

I've seen maybe a dozen companies with many partners utterly melt-down. One of which I was a part of.

This is something you'll largely need to answer for yourself. Everybody thinks their situation is different, but where partners are concerned, greed always seems to rear its ugly head somewhere, in some way you never expected.

My advice is to have a strong operating agreement, that nails down what to do if somebody goes and blows all the company's money at the club or other (soundingly insane, but) real things that happen. Also, the more obvious stuff that's usually covered by your attorney and a boilerplate doc - tie-breaking votes, voting when someone's unavailable, etc.