Tim, check with your service provider, see what they'll offer as an upgrade. And get them to run the analysis slide rule over your usage over the last year or so, and ask for a more appropriate tariff.
I did this at the end of March and T-Mobile moved me from bills of about £80-£90 a month to about £20 odd, including a vastly bigger data allowance, about 600 free texts and free calls. And they threw in a new Galaxy S2 for free.
I must admit though, as a relatively old foccer, using the phone has me bamboozled but being able to watch vids in full HD (I think) colour on my phone is amazing.
Mrs Diesel has worked for mobile service providers for 15 years or so and currently works for Tesco Mobile so I'll ask her what's hot and what's not when she gets home.