Well, the webcomics that I follow regularly are:
Sandra and Woo - Humor comicstrip
Gaia - High Fantasy comic, made by the same creators of Sandra and Woo
Gunnerkrigg Court - Fantasy comic with elements of sci-fi
Spinnerette - Superhero drama/comedy
Brawl in the Family - Videogame comic, in it's final run :'(
Ava's Demon - Space/Fantasy that's drawn in single-panel storyboard style
xkcd - Humor comic about technology, science, mathematics and relationships
Scandinavia and the World - Humor comic about stereotypes, history and culture
Rumplestiltskin - A retelling of the classic fariy tale
Also I follow some newspaper strips on gocomics.com