Great post.
For those that haven't tried this yet, keep in mind that you cannot recieve a phone call while your phone is being used as a modem.
Now that dedicated data cards are down to $49 to $149, it might be worth picking one up.
Also, at least verizon is slowly expanding their broadband access service (which their $149 cards are forward compatible with) and it offers 300kbps-2mbps speeds. They'll probably have phones soon that are compatible with it too. They might already. But I'd rather have a pcmcia card in my laptop for $149 than tie up my cell phone.
$80/month is a lot, but verizon (and probably other carriers) have started monitoring bandwidth and have the right to shut down your data connection if they figure out you're using the phone as a modem tethered to your PC to avoid paying the $79/mo.
Joe