[AUCTeX] recommended font for editing

[Frederik]

Hello there!

Some time ago I asked on this list, why so many symbols in 
LaTeX-fold-math-spec-list don't display properly showing just a box.
After experimenting with different "programming fonts" I discovered that 
my problem concerns the font being used in emacs (which is obvious, 
somehow...).
I tested Deja Vu Sans Mono, which is a free font, and realized that now 
some more symbols display correctly; still some remain boxes or don't 
show up altogether.

Now, what font should be used to display all these symbols? Any 
recommendations?

Thanks & regards,
Frederik