I'm on O2 at the moment with an iPhone 3G and their coverage/speed is extremely poor - they don't even cover my house.
I'm looking for a network that is reliable, extensive and fast, with fair data allowances. I'd love visual voicemail, but I guess I can live without it as it's currently, and for the foreseeable future, exclusive to O2.
Can anyone recommend a good network?
Many thanks...

I'm looking for a network that is reliable, extensive and fast, with fair data allowances. I'd love visual voicemail, but I guess I can live without it as it's currently, and for the foreseeable future, exclusive to O2.
Can anyone recommend a good network?
Many thanks...