I simply recommend all of these.

Internet

Inspiration
LooksLikeGoodDesign – Of course this is in the list, I edit it! Bucket of unpretentious design.
FFFFound – Constantly refreshing list of somehow noteworthy images.
Behance – Huge collection of portfolios by creative professionals across various industries.

Advertising
AdsoftheWorld – Great archive of advertisements, updated every day. Easy to use.
Joelapompe – Copycats of advertising.
This Ad School Life – As a student in advertising, I can relate to nearly all these humorous posts.

Downloadables
BrandsoftheWorld – Free .eps logos.
DaFont – Lot of bad fonts here, but a lot of good ones as well.

Services
Analytics – Undoubtedly the best analytics tool for your website.
WeTransfer – Free service to send large files.
FLVTO.com – Downloads videos/songs straight from YouTube.

Books

Advertising/Marketing
Hey Whipple, Squeeze This! – Luke Sullivan
The Copy Book – D&AD
Hegarty on Advertising – John Hegarty
The Idea Writers – Teressa Iezzi
Purple Cow – Seth Godin
The Decisive Moment – Jonah Lehrer
Nudge – Richard H. Thaler & Cass R. Sunstein
Yes! – Robert Cialdini

Misc non-fiction
The Seven habits of highly effective people – Steven Covey
Freakonomics – Steven D. Levitt and Stephen J. Dubner

Fiction
The Fountainhead – Ayn Rand
Atlas Shrugged – Ayn Rand
Alice’s Adventures in Wonderland – Lewis Caroll

Poetry
The Book of Questions – Pablo Neruda