Google offers a great variety of excellent typefaces free for web use (and print work). There are several ways to make the fonts available to your site simply by copying and pasting code. Start here.

The following fonts are particularly well-suited for web headings and titles.

Acme by Huerta Tipogråfica – high contrast sans; fun and informal
*Also see Lemon by Eduardo Tunni

Alegreya Sans by Huerta Tipogråfica – the sans version of a beautiful family of humanist typefaces; comes in many weights; I also love the small caps version (below).
*Also see Cantata One by Joana Correia da Silva for a similar, fancy serif

Bitter by Huerta Tipogråfica – a great slab serif typeface that is very even and easy to read
*Also see Arbutus Slab by Karolina Lach

Contrail One by Riccardo De Franceschi – severe, slanted sans is no-nonsense in-your-face
*Also see Carter One by Vernon Adams

Courgette (below) by Karolina Lach – great italic script that looks good at any size
*Also see Merienda by Eduardo Tunni

Dancing Script by Pablo Impallari – informal and still easy to read
*Also see Euphoria Script by Sabrina Mariela Lopez

Libre Baskerville by Impallari Type – beautiful; great for a classical or vintage look
*Also see Radley by Vernon Adams

Merienda and Merienda One by Eduardo Tunni – gorgeous brushy scripts
*Also see Salsa by John Vargas Beltrån

Marcellus (below) and Marcellus SC by Astigmatic – delicious, formal, and very graceful sans; low contrast
*Also see Tinos by Steve Matteson for a serif choice like Marcellus

Noticia Text by JM Solé – a lovely serif with a large x-height; very easy to read
*Also see Fauna One by Eduardo Tunni

PT Serif by ParaType- a very popular Humanist mixture; also comes in sans, caption, and narrow
*Also see Crimson Text by Sebastian Kosch

Quando (below) by Joana Correia da Silva – curvy and sexy; very easy to read in all sizes
*Also see Artifika by Cyreal

What are your favorite Google Fonts?