I think a combination of CSS reset[1] and CSS base[2] is the best way to go. Use CSS reset to remove all styles, and then use a standard CSS base to set a new set of defaults. That way you can easily distinguish between what styles are used for resetting, and which are actually meant for styling.

YUI does a really good job with this.

[1]http://developer.yahoo.com/yui/3/cssreset/ [2]http://developer.yahoo.com/yui/3/cssbase/