The key to this build is to get you both spell vamp and bonus damage with out having to back from your lane before level 6. For those Akali players, you know what I'm talking about when you reach level 6; it's game on! Twin Disciplines passive is very nice, giving you 8% spell vamp for having extra 20 AP and 8% magic damage for having 10 extra damage.

The other option that I've been thinking about is going with attack damage per level to get more spell vamp, but have not tried it yet.

Level 6, Combo sequence = Q-R-Auto-E-Q-R-Auto-E-Ignite
>Level 10, Combo sequence = Q-R-Auto-E-Activate Hextech-Q-R-Auto-E-Ignite
These combo's should be kills unless you got double/tripled with CC or going against a really tanky champion with gobs of HP. You should be going for their carry (AP or AD) and with this combo you should burst them down quickly.