Nokia 6110. The IR port was awesome, except that I never knew anyone else who had IR. It could be used to share contacts or play Snake two player (how that would have worked I have no idea). I believe it is the first Nokia to have had Snake.
After that I had a 6310i which was one of the better phones I've ever used. The blue-ish backlight was different from anything else I'd seen, I only needed to charge it 2-3 times per month.