I'm in the same boat. Cable comes out to a little over $100 a month for me.$40 for internet, $60 for hd cable + a dvr. If I drop the TV option, internet goes up to $60 or more. So cable is $40 more a month than internet alone. It's worth it for me to see college football, hockey and the occasional baseball game + all our shows are recorded. If more sports were broadcast over the air, I probably would try and ditch it.
Honestly I think they nailed the pricing model to get keep me hooked.
Internet & HD cable with ridiculous number of channels & DVR
$100
Internet
$60
Internet & basic cable
$60
Internet basic cable & DVR
$80
Internet HD cable with ridiculous number of channels & DVR
$100
At least I've got the option of two providers here. I have to call up and threaten to switch every few months.