All comments posted by Pastadiablo :

While I agree that your math does make sense, a few things have changed.  The reapers only do 30 damage with their D-8 charges (although that is still quite hefty), but they are relatively weak, with only 50 hit points, 5 less than a marine with the shield upgrade.  Also, marines can attack air units, whereas reapers are completely defenseless against air.

That being said, though, as you mentioned the only counters seem to be later on in the game (such as air units).  However, I don't believe Roaches and Stalkers are tier 2 - I think they are tier 1.  Namely because Roaches don't require a lair, and Stalkers only require that a Cybernetics Core be warped in after the Gateway.  While it's true that these buildings take longer than a Tech Lab at a Barracks does, generally the Reapers are most effective with the speed upgrade, which means if you consider the time it takes to produce Reapers with the speed upgrade, the enemy player (Zerg or Toss) should be at the point where they can and [should] have built Roaches and Stalkers.  

If the terran player does not wait for this speed upgrade though, he is likely only able to get 1 or 2 reapers into his enemies base before they produce the counter unit to stop them.  Building up a large force of 10 or so reapers would be pointless because by that point there would be maybe 4-5 counter units in the enemies base, easily able to prevent this force from being too destructive.

Also, the Zergling didn't cross the road because there was a siege tank on the other side :p

Team Liquid Invitationals LiquidNazgul vs. TheLittleOne

http://www.starcraft-replay.com/replays/liquidnazgul-vs-thelittleone-1269725011.php

One of the most interesting matches I've ever seen for SC2 so far.

Oh, replay of the weeks can't become replay of the months?  Not much incentive to become replay of the week then is there :p.  

How about this one?  whitera vs. thelittleone:

http://www.starcraft-replay.com/replays/whitera-vs-thelittleone-1269725240.php

Also a good match.