I would say:
1. Switch the next/previous page buttons when in landscape mode!!!
2. Fonts yes. Let us have a system font folder where we can put our own fonts that we can use throughout the system.
3. PDF margin restriction. A lot of PDF files have a huge horizontal margin that restricts the current zoom mode. Either have the option to set the margin that is ignored by the zoom mode, or have the option for a custom zoom ratio. We might be able to use the 9 and 0 keys to move the PDF to the left or right to get it properly centered.
4. Mobipocket support. The majority of downloadable content and in the ebook shops comes in mobipocket format. I believe support is in the works, but better sooner then late.
5. Small GUI enhancement in FB2 reader. When going to settings like page orientation or font size, it would be nice to have the current setting high-lighted.
6. Better HTML/CHM handling. More complex HTML files are messed up with the layout.
7. Big DOC file support. Have a 12Mb word file that gets rejected with a file size error. The same document converted to RTF with the same file size opens fine, just layout messy.
About the suggested clock in the task bar: Don't think it's a good idea, as mentioned it requires a screen refresh of some sort and at least every redraw/processor activity leads to battery drain. My primary reason for getting a dedicated ebook is battery life, beside the fact it's cool
