Terran vs Protoss is dependant on the strategies they use. Its of course essential to learn Lockdown/EMP, however to counter that the Protoss can easily use Stasis field to null half of your forces(might include your vessel). Psi Storm is also a good counter against tanks as two of them will kill them if they are in seige mode and has awesome range as well. Try Feedback vs the vessel too.

I feel that protoss vs Zerg is a war of who can get their units out the fastest, if the protoss player is slow, expect alot of Zerglings/Hydras to keep pressuring you as they expand(and they NEED units to expand). Otherwise, i feel a Dark Archon Maelstrom or Templar Psi Storm with basic units are going to win out. Watch for Plague though...it really hurts against protoss.

Zerg vs Terran is dependant on what happens...alot..Firebats can easily wipe Zerg's Hydra/Zergling especially with Marine/Medic backup. Two fire blases and up to 3-5 Zerglings can explode; Firebats are devasting vs Zerg. Plague however is also a pain in the ass, especially if the pressure you afterward..as your buildings will eventually explode. Tanks are very good as long as they are backed up so no Zergling/Ultra is going to just one-handedly..kill them >_> Tanks are Zerg base killers as they tend to be smaller and more efficient in a sense(more splash too), therefore less buildings to kill. Zerg Lurkers though are very very deadly as they can kill ALOT of infantry in a few strikes. Make alot of comsat for those and quickly make vessels and protect them against scourges.

I admit it was a little biased as i am a Terran player...but Terran are not weak at all vs Zerg, you just have to choose the right units and counter..and mostly Firebats and Tanks are going to win out with a little support from Marine/Goliaths. Not to say Zerg is weak vs Terran either, but there is no way a Zerg can just so easily trump a Terran player, especially against base expansion as Terran can move and build anywhere as they please.