I think I'm going to get an iPhone 3G (the new version includes a GPS receiver and 3G support).
The main questions are:
1) 8GB or 16GB. The latter costs an extra £60. I'm currently favouring the 16GB.
2) Black or White? You can only get White with the 16GB option, not 8GB. What do you think?
3) Contract or Pay and Go?
My average spend is about 50p/month as I very rarely make calls or text, although I do normally carry it with me.
a) Contract : £160 for phone, then 18*£30 = £700. This includes 75 minutes and 125 texts.
b) Pay and Go : £360 for phone (which includes 6 months data), then 12*£10 (for unlimited data) + PAYG=£30 = £510 ish.
Note: the Pay and Go rates are not finalised - they were temporarily visible and hastily removed.