I haven't shared links for a while now. Here are some that aren't in my sidebar---in my mind, these are the best of the best out there:
Justin Gerard: If you aren't familiar with his work, you need to be. His latest series for the Hobbit are some of the finest examples of how to handle comlex composition that I've seen in illustration.
Dave Guertin and Greg Baldwin: Two artists from Insomniac. The energy in their drawings never ceases to amaze me.
Erwin Madrid: Great style, lighting, and composition.
Jason Seiler: The most amazing caricature artist since Sebastian Kruger decided to get all serious on us.
Annette Marnat: Beautiful, fluid lines.
Mike Lee: Has awesome designs and a great handle on values.
Ben Caldwell: Has a fantastic sense of design. The Wizard of Oz picture I'm working on was actually inspired one of his drawings.
I have more, I'll post them next week.