I finally killed it

My beloved Nokia 6310i is in its death throes. It turns itself off after a maximum of about half an hour and can hardly be coaxed into action again each time. Possibly leaving it outside in the rain all night was overly cruel and unusual - although it has previously recovered from being accidentally thrown down the loo. Whatever - it is an ex-phone.

You've guessed what's coming next, yes? Solicitation of opinion. I have doubts whether there's anything to match the 6310i on my criteria, given that they're going on eBay for over £100 still, but I don't know what's out there. I've been using a 6310i for about four years. Surely someone's built a better business phone by now?

The criteria? Here you go:

I care greatly about:

• battery life. Huge, please. The 6310i lasts at least a week.
• good interface usability. (Motorola's interface is pants, for instance)
• rock-solid bluetooth reliability
• infrared
• robust build
• keeping my existing number
• staying with Orange (although I'm careful not to let them know that)
• compatibility with existing phone chargers, of which I have several

I care little or nothing about:

• colour screens
• video
• camera
• internet etc - I have a Palm PDA which does all that
• music players
• ringtones
• street cred

Go on please. Opine.
Please?