Well, this one's easy: How about including the really beautiful font "Gentium" (available at http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&item_id=Gentium)
which is licensed under an open font license and is stunningly beautiful, not to mention it fully supports thousands of languages with all of their "unusual" glyphs etc.
It is probably exxagerated to start a whole new topic, but I thought that the new rendering of fonts in SL is really great, so adding some other high-quality fonts could be an idea, and Gentium is definitely worth it to be included already in the distribution to gain a wider audience...
