Apart from the obvious design communities, here is my list:

FWA Great for micro sites and innovative ideas - a few legendary design agencies owe them selves to this site.

Site Inspire If you'er looking for "hip" design inspiration.

Designspiration This has been my replacement for ffffound.

Abduzeedo This is pretty much an all rounder for inspiration in design.

Fubiz All rounder again for inspiration in design - their content is usually top quality.

Benbentobox Great little tumblr feed based on colour themes for imagery - nice for colour inspiration.

Y Combinator Good if you want to keep one's ear to the ground on the start up industry in general.

Producthunt Use this to stay up to date with the latest tools and start ups.