The morale of the story is: if your data is that important to you, and it is within your means to do so, make it a habit to back it up yourself and do so regularly. I know it's an obscure concept but just think about that for a second before you go all sue-happy.
Should Danger & T-Mobile be reprimanded? Yes. Should Sidekick user be compensated? Yes, though I'm of the opinion that the free month & $100 gift card is very fair to 95% of sidekick users. Remember, in a court of law you have to prove ACTUAL monetary damage. You CANNOT use hypothetical cases of monetary lose or apply arbitrary value to your data. You are not entitled to millions of dollars if the data you lost is for numbers of a few kids. You don't get squat if your calender lead you to missed out on your American Idol appearance--even if Simon would have told you you were the best ever. And seriously, storing your ONLY copy of song lyrics on a sidekick (or any phone for that matter), is she nuts?