Glyphs: Soul Link, Howl of Terror, Corruption, Shadowflame. You should get Shadowflame and Soullink in all cases.
Specc:
http://www.wowhead.com/?talent#IMxMburNkVAMhkt0Gbhkhb
You can change the 2 points from imp. Healthfunnel in imp. healthstone, if you want.
You can also drop Soul Siphon if you never need the execute and put the points in suspression & imp coa. Some people like to get other things like imp fear, but i prefer this specc, it has probably the greatest offensive power.
People don't go Aff in 2s because its a shit bracket, you just can't win against Warr/Heal and other Meele/Heal teams unless they are retarded. As Destro with a Disc Priest you can atleast try to burst them fairly good and you can survive longer than 20 seconds like with a 2dps team.
@Drooid
I think death's embrace only works if you reapply the dots. Also glyph of siphon life is pretty wasted, glyph of Shadowflame is better for survival, having the option for a 70% slow is invaluable.