I believe the mortgage add some interest in it (whatever the interest you pay on your mortgage), but honestly, I rather go that route and have a peace of mind than have to worry on every April and November to come up with the cash.
Our tax bill is roughly $1100 a year. I set aside $100 a month in a seperate account. Come December, I don't worry about coming up with a chunk of money to pay the taxes. I can't imagine having to pay some of the tax amounts that have been posted in this thread!