My favourite (and most used) reader is iSilo, followed by Repligo, and Plucker (also left off the list....
)
I used Plucker before I discovered iSilo, but I love the speed and versatility of iSilo, and it's ability to convert html and text into very viewable format (especially on hires machines like Clies).
Repligo is excellent for everything else, especially PDF and Word documents where the page format is important. I miss some features, though - a find/search option, being able to remember what page you're on in ALL documents you've opened, etc).
Plucker is still installed, but only on my memory stick, and only for docs that I can't find or create in iSilo format
