What I use most:
ListPro Todo lists. I also use it to structure all kind of ideas and thoughts. It is basically a tree list. This is the only one that has
unordered lists though. You can drag items up and down to reorder them.
eWalletFor all my passwords, credit cards etc. I use a long complicated password. If I lose my pda and someone finds it, it is unlikely they can crack the database on a PC.
iPhone: eWallet is also available for the iPhone, ListPro is in the works.
Sbp Backup.
Very important.
PhatPad
for scribbling/drawing notes. Not perfect but better than the others I tested. They also have a program that translates your scribbles into ascii but it didn't work for me.
PocketInformant
Calendar replacement.
MobiPocketEbook reader. They also have an ebook creator. Both are free. You can use the creator to convert .txt, .pdf or .html files to the mobipocket format.
Resco Photo Viewer
There is also a good free viewer, don't remember its name. The Resco viewer is faster though.
TotalCommander
Free file tool. I use a commercial one because I like the design better but TotalCommander is actually better.
If you want a video player get TCPMP.
I also have a lot of SlovoEd dictionaries as I usually read in English.
I also use Wisbar Advance and Wisbar Advance Desktop for task switching. Setting up Desktop is a lot of work though.
