I personally wouldn't get a Nokia again. I have had no end of trouble with my N97, it's the worst phone I've ever had - constantly crashing.
There aren't that many apps either for the Nokia on OVI store, and the apps that look half decent are foreign.
I don't think you can beat iPhone for apps, I would go for that if I were you.
Also, Orange and T-Mobile have merged offering the biggest network coverage out there, they are called Everything, Everywhere Ltd