I currently have a small Orange phone on contract, An orange Dongle and a Blackberry on O2. It is a bit of a nightmare to manage and my normal phone is starting to get frayed around the edges and O2 Keep messing up the Blackberry billing.
I decided enough was enough and bought myself a Nokia N900. This has a data plan as well as the voice and can be tethered to my computer to give it internet access. By cutting out all the above phones I am saving over £50 a month and the new plan is only £20 a saving of £30 a month.
The big advantage is I only have to carry one device around now. I have been playing with it for 12 hours and the only thing lacking was contact grouping but this was fixed by a free app.
So far I found this to be a much better device than the iPhone. The iPhone was slick but failed on so many levels. The N900 took a little getting used to but is rapidly becoming a good friend.