Actually, points (pt), ems and pixels are all valid measurement units for these properties. Most of the suggested changes will have no effect as they are 0 anyway, but you probably don't want to remove the padding that is giving the nav lists breathing room above and below, and you certainly don't want to set the line-height to 0.

The standard fix for the posted problem is to change that <br class="clearBoth" /> to <div class="clearBoth"></div>, though just deleting it will probably work fine in most cases.