Usability News examined 12 fonts:

Sans Serif Fonts
Serif Fonts
Ornate Fonts

Agency FB (Agency)
Arial
Comic Sans MS (Comic)
Tahoma
Verdana
Courier New(Courier)
Georgia
Goudy Old Style (Goudy)
Century Schoolbook (Schoolbook)
Times New Roman (Times)
Bradley Hand ITC (Bradley)
Monotype Corsiva (Corsiva)

View a sample of each font type.
22 participants took part in [...]

A new study published by Usability News reveals very interesting information:
Passages formatted with 95 characters per line result in faster reading speed when compared to passages formatted with 35, 55, or 75 characters per line. At the same time 55% of the study participants chose 95 characters per line as the least preferred [...]

Example of CSS-driven tabs
CSS Tabs with Submenus