(The software names have the links to the websites.)

Of course there are many alternatives to these on the Palm platform, but I use these because they are very fast to use.

For example, to enter a new appointment for tomorrow, I need:
1. hit calendar hardware button
2. tap tomorrows day in calendar
3. tap on time slot
-> enter text (in-line, no pop-up box)

ThoughtManager also works similar way:
3 taps to get to my place
in-line text editing (no pop-up box)

SplashID is available for many platforms (except Maemo), so it is easy to port the data from one device to the next.

The other thing that I use a lot, is the desktop sync, I usually enter the large amounts of data on the Desktop, and read/update/correct on the phone.