Ditto on the above, especially a text editor and the Midnight Commander.
A .LIT reader or plugin for FBreader would be extremely helpful. Not the DRM version, but non-DRM versions. There are a couple of converters out there, so the format must be documented somewhere, and it would save converting a lot of files before being able to read them. It would also jump the iLiad to the head of the pack in terms of number of formats supported natively, I think.
I'd also really like a simple sketch program that could support pressure sensitivity, in the hopes that once the basic stylus calibration is done, pressure sensitivity will be supported.