Incomplete said:
use dslibris. only takes .xhtml though. not hard to convert. i have a useful set of tools that will convert html -> xhtml and txt -> html.
For the longest time I was booting into windows to use a bunch of tools to convert and TIDY files so they'd work with dslibris. Easy txt 2 html was particularly slow with big text files. I only just realised that the whole time Mac os X's built in text editor (TextEdit) can be set (via the preferences) to convert txt, rtf, whatever you can load into it, into xhtml 1.0 strict format in a matter of seconds.
DSLibris is not small however, around 2 meg with fonts BEFORE you start adding books. Big novels can reach 2-3 megs on their own, larger still if poorly converted (all that extra paragraph mark up).
You still cannot multi bookmark (in the latest version you can place the bookmarks but not navigate to them sfaik)
Customisation is growing by leaps and bounds, you can set margin heights and widths (how close text will render to the edges of the screens) now, and the xhtml display supports bold and italic text, more foreign characters as well as more punctuation (em and en dash and spaces). Font, font size and paragraph spacing are also customisable.
I hope the clock makes a return. I also hope they'll let us pick the page number font size individually from the body text size.
Its easily the most used application on my DS.