My pick for this post is Jeff Bandelin, creator of the (in)famous Tankmen series among other animations. The reason I chose Bandelin as my artist is his ability to create a convincing animation using very little hand drawn animation. He excels at creating an animated world complete with (relatively) lively characters despite the fact that very little of their movements are actually animated. Take for example the hand movements in his Tankmen cartoons. They tend to consist of one or two frames, but he is quite adept at hiding this by having enough tweening (movement done by a computer) going on that one does not notice how little movement the characters are actually doing.
Bandelin's animations are excellent not only for his ability to animate, but for his abilities in writing clever and humorous dialogue, dead on voice acting and overall tone of his shorts. He is a bit of a powerhouse in his ability to do all of this himself. Some of his non-Tankmen related cartoons are even more impressive for their ability to create detailed figures and still move them effectively without breaking the illusion or doing much hand animation.
His work (specifically his backgrounds) resembles Fritz Scholder's (Kate's pick) in its graphic, messy quality. His work is done this way in order to not draw attention from the foreground, but it is highly notable in that it fits the tone of his cartoon exactly and works perfectly. His animation is probably on Youtube, but I refuse to look for it there and post it here since it can be found in far better quality without being stolen here: http://johnnyutah.newgrounds.com/flash/. Seriously, take a look at it. Have a laugh, you'll enjoy it. Since we're supposed to post pictures, I'll add some of these, although his illustrations do not show off the qualities that I have been ranting about nearly as well as his animations (it does not stop them from being entertaining mind you, but rather consider this a warning that they are not nearly as connected to the point of this post as the animation). His flash cartoons can be found at the link above and his illustration work can be found on his personal website:http://www.bandyhates.com/