When showing the fonts that are possible for a document, it would be nice to see the font name as a preview of that font family. Also, when selecting the size it would be nice to show the current font in the selected size so you get a feel for the font family at the size.
I am using this on a Sony PRS T1 e-ink ebook, where the processing of choosing a font is quite slow due to the inherent speed of e-ink and reader cpu's.