I'm in fact reading this thread on my phone, trusty old SE p1i with opera mini, while I'm on the bus. I'd love to have a new phone, but I do have some critiria that need to be satisfied:
* simple way to switch on/off battery sucking features like 3G+/wifi etc. GPRS over GSM is quite sufficient most of the time and uses a fraction of power.
* stylus input, I type a heck lot faster with stylus than I do with onscreen keyboards, and a bonus is that I don't have to look at phone while typing - great for meetings.
* fully localized, on my p1i I can easily switch between latin and cyrillic input for example.
* fully functional mail client that can handle multiple IMAP accounts each with large number of folders that contain tens and hudreds of thousand emails. ProfiMail does this on my p1i today, the iPhone mail app is a joke and ibizmail is just slightly better.
* integraton of apps. One addressbook for all apps, user defined default app for web, mail etc. Easy methods for following certain data from one app to the next, connecting addressbook entries in textnotes, calendar entries etc.
* battery life, battery life and more battery life. This p1i can last about a week if I just use it for occational web/mail over GPRS.
I do not need thousands of apps, I just need a handfull, but they must work well and not be just silly lightweight toy apps like they typically are :p