My preference for AoE is unholy due to the high dmg of the diseases especially when spread with pestilence and Unholy Blight.
At level 60 Unholy blight will not be an option with 5/5/5 but you should be able to put out a lot of threat by loading up your target with your diseases and spreading them with pestilence to other targets. Throwing a DnD on top of them will boost your threat even more, though i recommend getting the DnD glyph, it is not a requirement.
On single targets like bosses, i usually just load the boss up with diseases use scourge strikes, and blood strikes dumping runic power with death coil.
Here is the build I would use for that:
5/5/41 Edit: Wall of text was bad.
Edited, Dec 22nd 2008 4:10am by Powerburn