Pre-Paying Mortgage: Pros and Cons

I have read all the pros and cons of pre-paying your mortgage. I had been a convert to the pay-it-quickly mindset - and have been typically putting in double the principal payment each month. However, I have now reconsidered. I am now putting just the regular payment (rounded up to the nearest hundred - old habits die hard!). The argument that won me over was in a blog comment (unfortunately I don't recall which - perhaps Get Rich Slowly). The argument goes as follows (paraphrased in my words):

The problem with mortgages are that they essentially reset every month. The fact that you prepaid thousands of dollars of principal this month does not mean anything as far as the next month's payment is concerned. If you miss the deadline next month - you are in default and are soon looking at foreclosure. We don't know the future - shit can and will happen. Instead of pre-paying the mortgage, put that additional payment into a dedicated investment account with a low risk interest bearing instrument. You will get the same or more in return as the after-tax mortgage rate - so you are not losing money. But - now you have the flexibility of continuing to make your payments. If this reserve gets too big then take a portion and make a lump-sum payment to your mortgage. Best of both worlds!

I completely agree with the argument above. I am growing more risk-averse as I am growing older - and this fits with my evolving risk taking profile. Mitigate the risk of future default by keeping aside the mortgage prepayment money. It will still go to the mortgage - but at a later date of my choosing and after working as a foreclosure insurance.

Since I just got back from Rome, here is, in my opinion, the best sight in Rome. The Sistine Chapel Side Frescos. Yes - the ceiling by Michelangelo is great - but I found the side frescoes to be the real star. The one below by Botticelli, called "The Temptation of Christ" is my favorite.