Buying an iPhone 5

Current prices for the 16-GB iPhone 5 are as follows:

Unlocked: $649.99
With 2-year contract: $199.99
One-time activation fee: ~$36
If you buy the 16-GB version from Verizon Wireless:

Share Everything Plan: $40/month
Data Plan of 1 GB/month: $50/month (you can add 1 GB for $10/month extra if 1 GB is insufficient)
Total: $90/month plus taxes

If you buy from AT&T:

Nation Plan: $39.99/month
This includes 450 anytime voice minutes, 5,000 minutes on nights and weekends, and unlimited mobile-to-mobile minutes.
Data Plan of 3 GB/month: $30/month (you can go down to 300 MB for $10/month less)
Total: $69.99/month plus taxes

If you buy from T-Mobile, their pricing strategy is somewhat different.  Essentially, you are buying the phone unlocked for $579.99 (which is cheaper), but you can choose to "finance" the phone over the course of two years by paying $99.99 up front and then paying $20/month for two years.  They are effectively giving you a two-year loan of $480 payable in 24 installments at 0% interest.  They do not have reduced-price phones if you sign up for a two-year plan.  That said, they have three plans to choose from, all of which come with unlimited talk and text (the variable being the data plan):

500 MB/month: $50/month plus taxes
2 GB/month: $60/month plus taxes
Unlimited: $70/month plus taxes

If you buy from Sprint:

Everything Data Plan: $79.99/month
This includes 450 minutes, unlimited messaging, and unlimited data.
Sprint also takes $100 off if you transfer your number.

For a two-year cycle, here is the total cost you're looking at (assuming you pick the 2-year contract for Verizon Wireless and AT&T):

Verizon Wireless:

$209.99 - phone (plus tax)
$35 - one-time activation fee
$2,332.80 - 24 monthly payments
Total: $2,577.79

AT&T:

$209.99 - phone (plus tax)
$36 - one-time activation fee
$1,814.14 - 24 monthly payments
Total: $2,060.13

T-Mobile:

$608.99 - phone (plus tax)
$35 - one-time activation fee (currently being waived)
$1,555.20 - 24 monthly payments (note: you are not locked into a 2-year contract)
Total: $2,165.19

Sprint:
$104.99 - phone (minus discount, plus tax)
$36 - one-time activation fee
$2,073.34 - 24 monthly payments
Total: $2,214.33

On price, the main issues with the Verizon Wireless plan are that 1) my plan (which is cheaper than this) is no longer available and 2) under the Share Everything Plan, you really need to have not just other people on your plan, but other people who use data.  Otherwise it's a waste of money (though note that it's only $21.57/month more than AT&T, which is the cheapest).

Another consideration is data usage.  I checked my data usage, and my average over the last six months is about 1 GB/month.  This month will be closer to 0.6 GB.  That said, 1) I tend to travel more than you, and I use more data then, and 2) I use my phone for personal email while at work, whereas you have the option to use your computer or work Blackberry.  It's probably a good idea to start with the 1 or 2-GB plan since overage charges are killer, but if you want to ease into it, you can usually save about $10/month if you go down to the 300-500-MB data plan.  Some carriers do not have this option, though.

Aside from price, one final consideration is coverage.  I don't have any good links (here's one, and this might be useful), but most of what I've read in reviews and the like says that Verizon is hands down the best carrier in DC.  Since the iPhone 5 uses 4G, there is some merit to this issue because 4G is not quite as ubiquitous as 3G or plain voice service yet.  Also, the Metro can still be a little spotty for some services.  You'll never get reception when you're under the Potomac River, but I find that my iPhone 4S (Verizon) does better than my Blackberry (AT&T) when I'm on the Metro.  I think AT&T is probably in second place, though.  And there is likely a bit of a drop-off for the other services.

B