First off - the title is required by most LLs in order to get a listing - if you dont have the meta title they will usually get turned down
Second - the description meta is what Google will use if it cant find a text snippet to use for your page in their listings
Third - Yahoo uses all of the metas as part of their ranking algo - they are the major that still uses the keyword meta as well.
Fourth - since it only takes a few seconds and will help immensely with SE listings - it is after all part of the SE's algos - why not? You will notice when searching in Google that the title when combined with on page factors plays a large part in the listing rankings
