I might pay $30-$40 / year for all google services together.
I really only use them because they're free. There are enough other services already I'd switch too if some of them became payware. I'm really not attached to any of the services. My gmail is filled with email forwarded from my own domain, so I could switch my mail provider without changing email address (as it should be).
I think the annual rate is a better way to convince people to pay. I really don't need another monthly bill to deal with, yet I barely think about forking over for my annual dns and web hosting bills.
I guess it depends on the service provided, but I'd definitely not pay $5/month for Facebook, but I might consider paying $25/year.
I really only use them because they're free. There are enough other services already I'd switch too if some of them became payware. I'm really not attached to any of the services. My gmail is filled with email forwarded from my own domain, so I could switch my mail provider without changing email address (as it should be).
Now, DNS, I am willing to pay for :).