I carried a Treo 650 for over a year before the Nokia E61 knocked it out of my hands. Now the only Palm OS devices I have are the Tungsten T3 and the Fossil Palm PDA watch. While the software choices for Windows Mobile have expanded significantly in the last couple of years, there are still some Palm OS applications that I enjoy using. I could use my T3 for these apps, but a better choice would be to run the Palm OS on my Dell Axim X51v Windows Mobile device. This is possible using the StyleTap emulator.
StyleTap has been in beta for quite some time and they just released an update that adds landscape mode, a Bluetooth virtual serial port, optimizations for Documents to Go, and more. StyleTap allows you to run most Palm OS applications on Windows Mobile Pocket PC devices and actually does it very well with fast responses and load times. The beta can be purchased for US$29.95 and this will include a free upgrade when the commercial 1.0 version is launched.
One of my favorite applications to run with StyleTap that I haven't found an equivalent for in Windows Mobile or Symbian is Tide Tool. I use this when I go out on salvage cases to help me calculate the ground reaction on a vessel at different times of the day. Are there any essential applications you miss from the Palm operating system that you would like to run in StyleTap?