Here is a summary chart of what I found while shopping online:

As you can tell the monthly cost of ownership between the iPhone and the Storm are pretty close.  The G1 is your best cost saver across the board, except for when you get into the unlimited talk, text, and data.  Once you get to that tier, the Palm Pre comes through as the cheapest.

Now some basic disclaimers.  I tried to put some carrier specific disclaimers on each chart listed below.  These prices were effective on 7/20/2009.  When listing the price for the phone, I took into account what offers the carriers had running at the time, regardless of if it was a mail in rebate or instant rebate.  The prices do not include any state or federal taxes.  Finally, all of this is based on signing your life away to a 2 year contract as a new subscriber.

Here are the rest of the charts:

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