Hermann Zapf is a legendary typeface designer. And one of his best-known works, Palatino, remains a very popular serif font throughout the world of LaTeX (and LyX). In LyX 2.1 (forthcoming) one can easily use Palatino in a document, either by selecting ‘Palatino’ which will usually use a free clone called URW Palladio or by selecting TeX Gyre Pagella, another clone based on URW Palladio but with a wider selection of characters.
The Optima typeface is a lesser-known font by Zapf. To my non-expert eyes it closely resembles the Palatino shapes, although it doesn’t have serifs. Hence I tend to think of this sans serif font as a “Palatino Sans”, and I often use it as a matching sans font for Palatino. I also find Optima useful for Beamer presentations.
In TeX Live one needs to install Optima manually, because of some license issues (the clone is not free as in beer). But TL provides a very easy installation procedure, especially on Linux (not sure about other platforms). As
You will actually be installing URW Classico, an Optima clone. Now you can
Tools > Reconfigure in LyX, and after restarting in
Document > Settings > Fonts > Sans you should have the
'URW Classico (Optima)' entry available.
If you encounter the
"!pdfTeX error: pdflatex (file uopr8r): Font uopr8r at 720 not found" error message, chances are that something fishy happened while installing the font. As suggested in this forum thread for Ubuntu users, to fix this you can (as root):
updmap-sys --enable Map=uop.map
If the above doesn’t help, then create a new file
as contents. Then (as root):
Update (05/10/2013): Include troubleshooting section.