The consensus around here seems to be that we are not punished in Christ. So I'd like to post my reasons for thinking that we actually are punished in Christ.
First of all, I'd like to point out that the particular punishment for sin is death, and the particular death that Christ suffered was crucifixion. So when Paul talks of us being crucified with Christ (Gal 2:20), or that our flesh or our self has been crucified (Gal 5:24, 6:14; Rom 6:6), or that we have died with Christ (Rom 6:8; Col 2:20), he is saying that we have been punished in Christ since death/crucifixion = punishment. (I should here point out that if we have died, then our death can only have served one purpose--the payment of sins/satisfaction of wrath. We have no ability to ransom, nor to act as a sacrifice for another.)
This is not mere reckoning (Rom 6:11). While it is certainly true that God reckons us dead, I believe that He does so in recognition of the fact that we really have died in Christ. The reality precedes the accounting, not the other way around. (Note that Galatians doesn't ever say that we are "reckoned" or "counted" or "considered" dead. It simply asserts that we are dead--as in really actually dead--in Christ.)
As further support, I point out Rom 8:11. Though you can argue that the suffering in this verse is not the suffering of the Cross (though I would argue that it includes the suffering of the cross), it is clear that we are indeed suffering with Christ in some manner. This helps to indicate what kind of union we have with Christ. (The prefix "sum"--"together with"--in Greek allows for no sense of substitution here.) This is not a mere union of reckoning. It is not a mere legal union. There is something more substantial going on here. Paul is not talking about the reckoning of suffering to us. He is talking about sharing the experience of Christ's suffering. This union is participatory, not just legal. (Though I must point out that it is a passive participation on our part.)
Thus, I feel that it is biblical to say that we are indeed punished in Christ. Prove me wrong. Either show where my reasoning is wrong by proving a) that we did not really die in Christ, or b) that such death is is not punishment, or else show that Penal Substitution is right by showing that the Bible says that we escape punishment.