Having/knowing the default font set(s) for the reading devices is very useful - if the original html/css calls it, one can more accurately simulate what someone reading the book on the devices will see.
And until embedding becomes oh-so-much-easier for the likes of me, that's the next best compromise.
I seem to have a copy of the Bitstream/Paratype: DutchRM BT Roman, true type, tt0011m_.ttf. It's in C:\Program Files\Sony\Reader\Data\fonts.
Dutch801 Rm BT Roman contains 377 glyphs and 418 standard kern pairs. This font does not include embedded bitmaps.
There's also a copy of Courier10 BT Roman, which is a monospaced font: tt0419m_.ttf. Courier10 BT Roman contains 377 glyphs and no standard kern pairs. This font does not include embedded bitmaps.
Not to mention Swiss721BT Roman, tt0003m_.ttf (Serif) Swis721 BT Roman contains 377 glyphs and 283 standard kern pairs. This font does not include embedded bitmaps.
If Sony's Dutch Roman = Paratype's Dutch 801, and for some reason you don't have it, it'll set you back a bill.
http://www.paratype.com/btstore/fonts/Dutch-801.htm
-bjc