If you have questions, i'd glady answer them since i tend to use my n810 a lot.
Like I said, a wallet program and the ability to install any program I may need to. Said programs need not be free as in beer. Anyway maemo is based on good old debian so I'm sure there will be tons of software available. What comes to mind are mutt, gpg, kismet...
Right ! You may browse through some of the available maemo software here:
http://maemo.org/downloads/OS2008/ http://www.gronmayer.com/it/
Specifically -- wallet - http://maemo.org/downloads/OS2008/security/ calender - http://maemo.org/downloads/OS2008/office-business/ (note that don't be turned off by the lack of screenshots on the page, the GPE suite of applications are marvellous. Screenshots are here: http://gpe.handhelds.org/
Another thing i'd like to mention is, unlike what you may have experienced with other devices, in maemo, the default applications that come loaded as part of the OS are good enough that you don't have to look for alternatives. Case in point -- although Evince is available, I find the default PDF reader much better suited. Also, although a whole bunch of mail clients are available, the default one is very suitable.
HTH, - steve