If you use a DWT template file to start your drawings, you may have noticed that they only come in one "version". In other words, now that the file format has changed, you can't use LT 2010 to create a template file that's compatible with earlier versions.
If everyone in your office is on the same version, you won't have any problems, but in a mixed environment some people may need older file formats.
In that case, simply save your template as a DWG file in your desired file format (2007, 2004, etc.), find it in Windows Explorer, and change the extension to DWT. You must have "Hide extensions for known file types" unchecked in the Folder Options for this to work.
(If you don't use templates yet, I highly advise looking into them...they're an easy way to start a new drawing containing standard layers, annotation styles, etc. without risking overwriting the original template file.)