I’ve been playing around with one of them Sony-Ericsson w810i’s and have been trying out the walkman capabilities this week. It’s better than I expected in that it only uses about 10% battery ever hour at < 50% volume. Actually the volume is an example of good design. They spent a little bit more money providing the consumer with in-ear earphones rather than the normal ones, which lets me listen to the same volume music with less battery consumption. So I don't get pissed off about battery usage, and my overall experience is better!
I've also replaced my keychain camera with the embedded camera. The noise reduction algorithms in the cameraphone is not as good nor is the flash light, but it’s useable as long as it isn’t too dark. It saves a lot of room in my pocket too, which is great. Also, I finally figured out that if you hold down the star key in camera mode, you can quickly turn on the light. The alternative to navigate thru a variety of menus is not fun.
The video mode is not bad either, if you’re ok with the low resolution. I tried to record some of the concerts at Virgin Festival Day 1, but the sound was too loud and it garbled the input. Although, if it’s a more personal environment, it is pretty well fine.