This question doesn't have a one-size-fits-all answer. A clubhouse should be built to reflect the memberships tastes, needs, and general lifestyles. Long Island would generally tend to have a big show and center for high society along with the golf. So, the facility would have grille rooms and such along with formal dinner and banquet facilities, etc. But, it has to be a membership that has the financial facilities to not be bottom line oriented to that extent.
For new clubs, or those that have had big membership demographic swings, I think the facility should start or be focused on the simplest or closest to consensus of bare minimum frills as the members will tolerate. It is always easier to build up to rising expectations than pay off and go bankrupt due to exagerated and over-reached facilites that become an albatross and a drag on resources that are needed to make the golf great. If golf is king at your particular club, then provide only what will support enjoyable golf and golf related activities. A room to linger for cards, and simple good food and drinks. Let them decide later if they want more...