The Greek word cheirographon looms large in the interpretation of this verse. It was the thing that was metaphorically "nailed to the Cross." So what is it? The title is a link to Crosswalk.com's lexical resources for this word that is free for anyone to check out. If you do you'll find that the word refers to a certificate of debt, like an IOU or a mortgage note.
Louw & Nida's entry looks like this:
33.40 ceirografon, ou n: a handwritten statement, especially a record of financial accounts (similar in meaning to grammad ‘account,’ 33.39, but perhaps with emphasis upon the handwritten nature of the document) — ‘account, record of debts.’ exaleipsas to kath hmwn cheirographon ‘he cancelled the record of our debts’ Col 2:14.
There's a neat Scriptural tie-in to this word, but I'm not sure how much I'm going to make out of it in the sermon on Sunday. When a cheirographon was declared "paid in full," the normal Greek word that they used to express this was tetelestai. This word might even be literally written on the debt instrument. One could imagine it being like the bank stamping "paid in full" on a car loan, or a mortgage on one's home.
In John 19.30, when Jesus breathed His last on the Cross, His final word was tetelestai, exactly the same word used to declare a debt paid.
There is a significant difference between looking at Jesus death as nullifying the Law under which we stood condemned because of our transgressions, and seeing that Jesus actually paid the price for our crimes. The thrust of Scripture alone should force us toward the latter, but our rebellious desire to believe that God has somehow become morally lenient since the Cross keeps us trying to hold on to the former.