Can we at least select our fonts?
status-completed Check out the resolution to this question: Fonts and the new Q&A theming
I think the fonts give much of the feeling to a site, and may even affect usability. For instance, English.SE benefits from using a serif font to clearly distinguish letters and make IPA more readable. Likewise, Judaism.SE's serif font makes Hebrew phrases (which are very common there) look much better. And on Math.SE the serif font makes MathJax formulas blend in nicely.
This isn't to say that serif fonts should be the standard. Sans-serif is quite fine for StackOverflow and other coding related sites. Indeed TeX.SE benefits from its sans-serif to distinguish rendered TeX. Sites that use Unicode characters extensively, like Japanese.SE, will want to chose a suitable font too. The same applies to the code blocks of Codegolf.SE that often have to display special Unicode symbols for which the default font is inadequate.
List of sites that need an alternate font for reasons other than just wanting to be different
Non-Latin source texts
Mi Yodeya (serif for Hebrew including vowels & other markers)
Hermeneutics (serif for Hebrew and ancient Greek)
Christianity (Hebrew + Greek)
Islam (serif for Arabic esp. for diacritics)
Hinduism
Buddhism
Literature (many scripts)
English Language & Usage (Greek, occasionally Cyrillic)
Notation
Code Golf (monospaced for programming languages with Unicode symbols)
Math (serif to blend well with MathJax)
RPG (serif to blend well with MathJax)
Physics (serif to blend well with MathJax ─feature request)
Chemistry (serif for formulas with support for special chemistry symbols)
Mathoverflow? (serif to blend well with MathJax)
already has styling, but have not chosen special fontMusic? (font that has various music symbols)
Mathematica? (font that supports its Private Use Area characters)
HSM?
TeX (monospaced to distinguish code from commentary)
IPA
Linguistics
English Language & Usage
Constructed Languages
Language Learning? (foreign scripts)
English Language Learners?
Cyrillic
Русскийязык
Russian Language
Stack Overflow нарусском
Ukrainian Language
East-Asian
Chinese Language
Japanese Language
スタック・オーバーフロー
Korean Language