I recently purchased an N800 to replace an aging Palm Tunsgten C. One thing we really need to get straight is that the 770, N800 nor the N810 are not intended to be PIMs -- so you must set your expectations accordingly. Also, the software platform is not quite mature -- in the sense that some actions are doable by using fingers, but others require the stylus. You would think that the built in software would be designed to work in either finger or stylus mode but some buttons are too small to accurately select...

Just to give you an idea for the conversion, here is a quick outline of the main software packages I was using on the Palm and how I am currently handling its function under the N800.

On the palm, I was using
1) Dataviz' BeyondContact for PIM
2) Documents To Go for document viewing
3) SnapperMail for mail
4) Palm's WebBrowserPro for browsing
5) ZLauncher as the app launcher
6) QuickNews for RSS reading
7) JFile for personal databases

The applications have been mapped to the following maemo software:
1) GPE 2.8 -- I am using my own build with some minor enhancements (calendar, contact(modified to use a finger based telephone-like name search (see contactspro from http://www.MobiMate.com), file-manager (modified to view hidden files) and gpsyncd (modified to handle a number of character sets besides UTF-8 when importing) and erminig to sync with Google calendar.
2) I am currently working on a modified AbiWord to be used for this purpose, but the basic build of 2.5.2 (without hildonization) run pretty fast and looks very good. For spreadsheets, gnumetrics is very good. Just needs something to view powerpoints. The internal PDF viewer is ok.
3) I am using the default mail software (because it is tightly integrated in the GUI), but would switch to Claws-Mail if it could replace the built-in one (including GUI integration)
4) I use the built in Opera browser
5) I think the N800 launcher or "front page" is really, really weak -- what is this idea of a menu system to launch an application? I should be able to put my applications on screen and tab between groups. Right now I use the simple-launcher -- but I am looking at implementing a tab based launcher for chinook
6) the build-in RSS reader is lame and I only use it because of the desktop applet. I use Claws-Mail with the RSS plug-in to read it. Just wished it had a mechanism to refresh every x hours.
7) I am using gnumetrics to manage my databased. Not ideal, but it works. Will be looking at leveraging sqlite3 since it is used by GPE 2.8, but need a nice GUI front end.

So yes, migrating is feasible, but the functionality after the switch is not quite up to par to the commercial software that was available on the Palm. Obviously, it all depends on what you use the device for.

Hope this helps,

Robert B.