If your company want lots of casual interaction with your clients, you must determine the type of client you will normally have and what will make them feel comfortable with things they like but at the same time feel a bit classy and modern updated. Nine times out of ten people do not want to downgrade.
Your Company environment must also be highly functional. If your selling certain items those things need to be displayed with class. The furniture you select must not only reflect what you like but what your customer will feel is valid and they can ok it or approve of the office environment when they arrive.
As far as thinking about the best environment for the company employees. Companies today don’t want an environment that is unhealthy, totally unattractive to the type of employee you want to attract and keep, or does not make it easy to do their jobs effectively as possible.
If you want to give a very established, confident and authoritative look you would want to go with more traditional style of office furniture and set up. If you want a progressive selling environment, you want a contemporary style new feel with a heavy contemporary style. In a creative environment you definitely want to mix it up and use a modern furniture flair and creative room environments combined with some practicality for job function and organization.