ScFou vs. IMNeatea GSL Semifinal Game 5
http://www.youtube.com/watch?v=nH4_itHLpnk
Great play, great ending. One of the best SC2 games ever without a doubt.
MouzThorzain vs. DigitasNaniwa TSL Finals
can be found at the teamliquid youtube channel
http://www.youtube.com/user/teamliquidnet?blend=1&ob=5
Seriously start at game one and watch through game seven, not a dull moment, great games in the finals of a massive tournament.
MC vs. Losira MLG Columbus Loser's Final Game 2
http://www.youtube.com/watch?v=Z-sEt3m4m_Q Game 1 is good, but Game 2 is the best of the series.
Insane attacking play from Losira countered by great calm play by MC
Those are the ones that came to mind off the top of my head, I'm sure there are others (IMMVP had an amazing comeback in a TvT but I can't remember who it was against). But that should get you started.