Many restaurants have private dining rooms that can be used for brunches, lunches, dinners and cocktails parties for business or personal parties–that are not in the main dining rooms, quieter and provide an atmosphere for discussion.
You can negotiate a price fix menu, special cocktails, and ask about special touches or bringing in your own floral displays and special touches.
For business events, it’s much quieter and can be less expensive and provide audio/visual equipment for a guest speaker and/or sales pitch.
For personal events, the hostess(es) can enjoy the event, it can be disability accessible, more elegant and no clean up required.
Cost it out and compare the price, time and people involved to hold a similar event in an office or banquet facility or home. Ask the restaurant if it has a slow period or season, and offers with special discounts. You may think it more expensive, but will actually being saving money because of the time and people needed to hold it elsewhere.
Websites like this one list provide locations, details and prices by cities: http://www.opentable.com/info/banquets.aspx?m=3