In this day and age of large, widescreen monitors, you want to be able to flow and layout of your site no matter what the width of your visitors' windows are. Here is a quick how-to choose a fluid or fixed layout:
For Telligent Community:
For Telligent Enterprise:
The Telligent Community version of this video is posted here in the 5.x documentation: telligent.com/.../select-a-site-theme.aspx