i can't believe no one has said this yet....
2/2 improved drain soul.
it's needed for the 10% threat reduction... doesn't matter how crap your gear is, there will always be situations where threat is an issue (mainly threat capped bosses) so this is a godsend.
also if you've got less than about 25% crit rate, UA > ruin for an afliction warlock, so i'd swap 1 point in devestation and ruin for:
3/3 malediction
1/1 UA
the reason why I'd suggest malediction is because if you have at least 1 extra shadow caster or two fire casters, CoS/CoE will be a larger raid dps increase than an afliction lock using CoD. also if you're doing a 10man with only 1 shadow or fire caster you should be using CoReclessness. roughly a 5-6% dps increase to melee classes, also the increased healing requirement is minimal at best with the exception of a few bosses (gruul, mul'gar, prince Phase.2, nightbane being the main ones to worry about, for just about all other bosses CoRec isn't an issue, especially with a good tank / a few good healers)
POST EDIT
this is the build I'd suggest Edited, May 18th 2008 9:37pm by Jenovaomega