The most useful site I've ever seen for the artist

I personally have not signed up for this site, but I can vouch for its use.

http://www.conceptart.org/

If you doubt, I will direct you here

http://www.conceptart.org/forums/forumdisplay.php?f=41

(Critiques by excellent artists the world over...mostly)

here

http://www.conceptart.org/forums/showthread.php?t=152626

(The best art books that anyone can find use for)

here

http://www.conceptart.org/forums/forumdisplay.php?f=42

(Comprehensive, massive, FREE tutorial section)

here

http://www.conceptart.org/forums/forumdisplay.php?f=12

(Jobs.)

and here

http://www.conceptart.org/forums/forumdisplay.php?f=15

(Things I learned through experience that could've been learned for free)

I found these sections extremely informative. This site has a lot of depth. If nothing else, check the stickies from the sketchbook and art school section (ESPECIALLY THE E-BOOKS). If you're a braver soul, go ahead and register and get critiqued into perfection.