Distance matters, There are several base stations within 1Km of my home.

Check this article on 3 about their all you can eat package.
http://blog.three.co.uk/2011/03/04/guest-post-all-yo...

An article featuring 46 Gigs of mobile data usage.
I've recently got a 3 premium dongle and 15GB account and I'm planning to get a Samsung Galaxy S2 with 3's all you can eat data plan when they come out in May. This phone is hspa+ too which should get speeds similar to my dongle and they will both get higher speeds when 3 update their network this year.

That may be true, but as you'll have read from the other responses, mobile broadband is not without it's own issues - least of all the fact that "unlimited" data is often written with an * next to it leading to lengthy terms and conditions about how it is not "unlimited". Then you've got all the claims made by providers to outdo each other and get your custom yet probably only 5%-10% of buyers will ever get the speeds quoted. 3 Mobile got one of their ads pulled for misleading claims.

If I were you, I'd buy a single data shot dongle on T-Mobile and try it out before jumping in to a 24 month contract!