Two weeks ago, with the initial frenzy dying out, and lines at the Apple Store once again down to reasonable lengths, I picked up a 3G iPhone.

Then, a few days ago, I left it in a cab on my way home from the gym.

At which point I discovered that, as I’d bought the phone with my American Express Platinum card, it was completely covered by their Purchase Protection Plan. A five minute conversation, a quick fax of the receipt, and they had credited the full cost of the phone back to my account.

Set aside the access to airport lounges, the free companion tickets on domestic flights, and the excellent, excellent concierge service (which, on my bachelor party trip to New Orleans, got us tables for seven at two restaurants – Chez Paul and Luke – that had claimed to be totally booked); the iPhone refund alone made using that card and that card alone totally worthwhile.

Don’t leave home without it, indeed.