Are you someone who has a ton of Palm OS apps and do not want to lose them if you upgrade to the Palm Pre? Palm previously said that Palm OS apps would not work on WebOS directly, but did leave it up to 3rd party developers to come up with a solution. As you can see in the video on PreCentral.net you will be good to go with the Palm OS emulator called Classic. Classic PalmOS emulator is from the folks at MotionApps and it actually looks pretty incredible. Applications run fast and may even be faster than what you see on many Palm OS devices today.
I personally use Tide Tool on the StyleTap Palm OS emulator and find there are a couple of Palm OS apps that are still only available on Palm OS. I also do think at some point it is time to move on, but with this application you can continue to live in the past with your classic Palm interface and apps.