The key I think is have a desk that can change (not fixed). I have the GeekDesk (http://www.geekdesk.com) and wouldn't go back to a normal fixed desk. Yes, I don't stand for long periods of time either. But I really enjoy the fact that I can change my desk height throughout the day. For example, I have a large whiteboard right beside my desk at standing height. So I flip the desk to standing position when I want to brainstorm and have access to my computer.