Arguable. you can go BT -->Zeal-->LW-->Finish PD--> Defensive item-->IE BT-->Stinger-->LW->BT-->BT-->zeph MASS BT.
or other stuff I recommend trying the 2nd one for fun. First build is used in high level play. --- "It doesn't matter how many resources you have, if you don't know how to use them, they will never be enough" -Masters Zerg