A 2 year subsidy is a good idea if you are going to get the data service anyway. You are locked into the same contract if you buy a data card or a usb modem anyway so getting a netbook on the cheap is a good deal.
$60/mo + overages is the problem. 5 gig is one DVD's worth of data. $60 bucks for 1 DVD. $480 per each add'l dvd per month. Wow. Pretty expensive piece of plastic.
Now $30/mo for say 50 Gig is another story. That's $3/dvd. Much better.