CSS Reset provides a good starting point.

“The basic reason is that all browsers have presentation defaults, but no browsers have the same defaults. (Okay, no two browser families—most Gecko-based browsers do have the same defaults.)”

http://meyerweb.com/eric/tools/css/reset/

http://developer.yahoo.com/yui/reset/

http://www.maxdesign.com.au/articles/css-reset/

http://stackoverflow.com/questions/116754/best-css-reset