Perhaps you need a conference room or a boardroom where confidentiality is important. There are partitions available where soundproofing is a necessity. You might also prefer low sided work spaces in some areas, in order to present a visually open space. Your staff will appreciate having their very own work areas. It will create a feeling of belonging as well as give them an opportunity to personalize it to fit their needs.
There are companies that specialize in designing office spaces. Have one of their consultants sit down with you and determine exactly what your needs are and have them draw up different configurations to choose from. There is something magical about seeing a dull wide open space turned into luxurious office quarters that you will be delighted to show off to your clients. Avail yourself of their services; you will be glad that you did.