It's a mystery for me to decide which one to keep in continuous use. Every one of those has a features which keeps me going back. Few to mention;
- Android; usability, responsive and clear user interface. Fast web browsing and nice outfit of nexus one.
- Sony Ericsson X10 Mini PRO; form factor and keyboard (I do also have plain mini, which is small!)
- E72: qwerty keyboard and basic functionality just works. A bit hacked refreshed components thought, like gallery and email. Symbian is outdated as platform, I see.
- Samsung B2700; free from worries, how to handle my phone. Just great in that part.
- N900; IM-integration, I just need my Jabber client (to company own XMMP server) among skype to handle few international contacts. Shame it's a bit clumsy and maemo got replaced with meego in future plans of Nokia.
- Hardware optimised for size with qwerty keyboard
- Open Linux based operating system, with non-US crypto parts, fast and clean UI.
- System without version numbering, modular and upgradeable all along the way.
- Multi account emailing with GPG support
- Standard XMMP IM-client, with possibly Skype and other proprietary accounts supported as well.
- Camera and video recording with good quality