[mGGPrometheus]

I think hellions make for great early game units from which to transition into MMM. If you make something like 6 hellions early game, you can:
1. Take a safe expansion
2. Prevent the zerg from taking a safe expansion
3. Punish him if he's taken a fast 3rd
4. Halt creep spread
After your initial factory, chuck down an expansion, 2 extra rax, 2 refineries, then get stim and tech to medivacs. You can then do a great push with MMM and hellions.