Hell, It's About Time: Let's Play Starcraft 2: Wings of Liberty Campaign Mode! (DONE)

[smuchmuch]

Goliath upgrades aren't that usefull if you already have somme upgraded siege tanks and vikings. I say go for orbital command, automated refiniries if you feel they would help you and keep the rest for somme better units upgrades later on.
You may want tio Hire the Hells angels and/or the Spartan Company at somme point. Mecenaries can be usefull in somme ofthe latest missions (if you decide to do "Shatering the skies" particulary)

And Engine of destruction next.