I'm mainly solo with voidwalker. I intend to use Shadowburn for PvP to up my killing blows and for runners in PvE. Those damn runners get me every time ><. I usually Immo/Corr/CoA and depending on the class go from there. If it's a healer I'll usually hit it with a couple of shadow bolts so I knock it out before it can heal itself. If it's big and nasty I'll also hit it with a few shadow bolts. If there are multiple pulls I'll use searing pain on one to get it off my pet and gone quickly, or i'll dot them all (3 max) and hit them with rain of fire (depends on how i feel). If it's just a weakling I'll save mana and use my wand.
On another note, I read through this forum and I agree with the arguments against Improved Drain Soul that I believe Evilturtle made. I was also thinking and decided that it isn't prudent to put 5 points into Improved Corruption to make it instant, because there's still a 1-second delay between spells. If I take two points out, it will be a .8 second cast, which will still be hard to interrupt even if for some reason my target is on me instead of my pet that early in the fight, and less time and talents will be wasted.
As such, I present my latest respec plan...
http://www.worldofwarcraft.com/info/cla ... 0100000000