So I decided that mutalisks being my favorite unit, I would try to theorycraft a build that would give me the map control I wanted to have a nice healthy mid and end game (which both still suck btw because I usually win out right with this build or lose because I'm a n00b sometimes). Anyway, here's what I have so far:
15hatch
15pool
14/15 gas (maybe 16?)
Get speed at 100g -> Pull drones from gas to mineral
Get about 32 workers total, then build the 3 remaining extractors, continue to drone so you have enough to have 16 mineral workers and 6 gas workers. From here, you want to build speedlings to retain map control or at least have some sort of threat and spine crawler. Get lair at next 100g, then build your spire when the lair finishes.
Your 3rd expansion is still a question to me. I think if you have the right situation, you should be able to pick up your third before you even start your lair, provided you have good map control. If you don't, wait for the mutalisks to get out (you should have enough for about ~14), then you can expand to your hearts content. Continue pumping out mutalisks (and air upgrades if you want) and drones.
The reason I don't build all spine crawlers is that I think it's important for your opponent, regardless of race, to see you have some sort of army. At my level of skill, people get scared and stay in their bases and try to send air harass or something to distract me or do some damage when they see my speedlings. Or they think they just need some AoE thing or more marines so they wait. The point is that it's really a mind game - the lings will come in useful later if you're fig
(These worker counts are basically me saying get 2 bases saturated with 2 workers to a patch, and gases)
There's no mid or end game to this yet. You can do whatever you want from here, imo. Depending how I'm playing, and their build, sometiems I'll stop making mutalisks and try to keep them (the mutalisks) alive as much as possible, then switch to roach hydra against most zergs, mech terrans, and heavy gateway based toss armies. I'm still doing some teasing, and I'm going to have to back to wings for a few weeks until swarm is out. Anyway, leave some thoughts and critiques if you want.