My favorite design site:
NOCOT This site is amazing. It updates usually about once a day and has the coolest stuff. Notcot.com has a lot of marketing and interior and exterior design. There are some amazing ads on there as well as very creative packaging. Very cool. Also, if anyone is interested in fashion design, sister site Notcouture is pretty neat. If you RSS Notcot.org you will be updated every time one of the sister sites is updated. Notcot.org just had a website featured: dyslexflix. :)
Yanko Design is a website similar to Nocot. I just recently found it. It seems as if it is focused more on design of the future.
Some good free sources: FreeVectors.net, SpoonGraphics, and ColourLovers. The first two have free designs while ColourLovers has some wonderful color harmonies for use. Pantone has also released color trend favorites for spring 2008.
Some typography sites I have flagged are: Typographica (recently they named the top typefaces of 2007) and a cool site with Kinematic Typography (this site takes famous movies and animates the dialogue--this would be a pretty cool assignment for motion graphics).
If you are ever interested in entering a graphic design competition try RSS'ing this site: graphiccompetitions.com
Cool ads: Coloribus.com-Advertising Archive
Hopefully that will get some people inspired. They are pretty cool things.