Better than Damagemeters is 
http://files.wowace.com/Recount/Recount-r53286.zip

With this it gives u dmg meter (including what attacks did what percent of your damage), heal meter, dps meter, hps meter, and my favorite.... it tracks the death of any member in your party so that you can check back and see the combat log of the last 15 secs or so b4 a member died which is great for determining causes of wipes (noob healers and people that cant follow directions are finally exposed)

Recount is also good for seeing who is using what abilities more often.  like if a dps warrior is using heroic strike too much or if a tank isn't using shield slam/revenge enough.

also, in raids you can watch live your total raid dps to gauge how you are doing for fights like Aran/Gruul etc.
just type "/recount realtime raid dps"