I never tried demonology, I figured they can take care of themselves...
yeah, warlock is one of the best de-buff classes in a group, they have put at least 3 DOTs on the monster, and the more "Instant" cast those spells are the better... anyway, here is a "suggestion" for talents... I found this in the warlock's forum....
This guys is going to for the full Affliction at the end, which is what I planned to do, so this is similar to what I would do with my warlock...
Affliction Talents (16 points) # Improved Corruption - 5/5 points
makes this instant cast. a must have.
# Improved Life Tap - 2/2 points
i use this in combination with bandages for very little downtime, since mana pot's are hard to come by and i horde money.
# Improved Drain Soul - 2/2 points
Gives you a 100% chance to get a 100% increase to your Mana regeneration for 10 seconds if the target dies while while you drain its soul. In addition, your Mana may continue to regenerate while casting at 50% of normal. extra mana regen is good
# Improved Drain Life - 1/5 point
i needed the point put somewhere, and extra life drained seems like a good idea to me
# Amplify Curse - 1/1 point
once every 3 mins, but extra dps is nice.
# Improved Curse of Agony - 3/3 points
extra dps
# Fel Concentration - 1/5 point
when i do use drain life, it's usually to proc nightfall. sometimes this aggros the mob, and 14% is much better than 0% chance of avoiding interruption.
# Nightfall - 1/2 point
this procs more often for me than you'd think. insta-bolt is sexy
Demonology Talents (2 points) # Improved Healthstone - 2/2 points
personal preference. i like the 100 extra hp applied
Destruction Talents (17 points) # Improved Shadow Bolt - 5/5 points
self explanatory
# Bane - 5/5 points
# Shadowburn - 1/1 point
nuke, pure and simple
# Devastation - 5/5 points
i want ruin
# Destructive Reach - 1/2 point
Also if you need a Complete Guide about Warlock's talents... here is a helpful link but lots of reading:
forums.worldofwarcraft.com/thread.aspx?fn=wow-warlock&t=83709&p=1&tmp=1#post83709