immortals are really good against buildings too.
If i remember right, this is a really good TvP replay...
Theres another one out there where T is on scrap station and does a bunker + siege approach, I can't seem to find it though... might be on BlizShouter or huskystarcrafts channel...nvm found em.. but T won both games..
But there is a pretty good replay of what units counter against those races...
I found also that the round of 4 by team liquid replays are good too