In your case ... keep the broadband.
Using any other form of internet access will cost you dearly .. apart from being less reliable.
If you said just email and bills .. ok .. mobile maybe cheaper.
As soon as you start browsing eBay or other sites that load pictures, etc, you will be screwed by the amount of data transferred.
I like the way you leave it on and it is your 'book about everything' Doesn't your Googling add up to a few hours per day?



