The sites and blogs I visit the most are mostly about music or design/photography since they're two of my biggest passions. Here they go:
Music Related:
Edited *See TFS Community Rules regarding self-promotion
Kinosport: Mp3 blog with a lovely design and often insightful posts. Focus on electronica.
Gorilla vs Bear: Arguably one of the most popular mp3 blogs. His music taste and mine is an almost perfect match, I really like the music in there.
Said the Gramophone: Another mp3 blog. Although I don't like the music in there half of the times, it's always worth the visit if only for the amazing stories that join each song.
Raven Sings the Blues: Mp3 blog with lots of emphasis on garage rock and psych-folk. Love it when I'm feeling gritty.
Dusted Magazine: music reviews, pretty eclectic.
Pitchfork: more music reviews, emphasis on indie.
Resident Advisor: electronic music reviews.
Design/Photography related:
Foto Decadent: Fashion photography community.
Creative and Live: Wicked design. Ezine about design and photography.
Grafica Colectiva: Showcases other artists portofolio. Good selection and very nice design.
Creative Output: Some very beautiful selections for the most part.
Grain edit: For the nostalgic child in me.
Lolitas: Another great source for beautiful shots. Not about actual lolitas as the title might imply.
BibliOdyssey: Scans of old books, many with fantastic ornamental illustrations. A good source for historic inspiration.
Yatzer: I like it because it's not as bloated as similar showcasing sites and they post some very interesting design ideas.
Iso50: Musings on retro objects and smart design.