[ShellShock]

I also use Georgia at the moment. I have dabbled with Fontin and Charis in the past. Georgia and Charis are good because they have a lot of unusual gylphs lacking in many other fonts, e.g., ligatures for "ffi" etc. Some rendering engines (I am thinking of Adobe RMSDK as used on Kobos etc) automatically convert multiple characters (like "ffi" in the word officer) into the single character ligature, and if this is not in the font then it will be displayed as a blank.

I use the attached epubs for testing fonts, as they have a lot of unusual characters in them.