Ha. Workspace. That implies both that work is done there, and that there is space to do it in. HA I say.
1: My wacom tablet. If you're serious about drawing stuff digitally, beg borrow and plead if necessary, but get one. It does take a little while to wrap your brain around the new medium, but it only takes a week or two to get comfortable inking scanned drawings. After two years of use, there are only a very few things (cross hatching, dragon scaling, and laying out of proportions) that I prefer to do by hand.
2: Upright mouse. It's ergonomic. When I was working 8-10 hrs a day in Adobe Illustrator, this saved me butt. Or rather, my back.
3: Pile of chainmail stuff, some of it in progress. Handily available for when WoW logon cues are long.
4: Whiteboard. Extremely useful for keeping track of 'oh yeah... I need to-' sort of tasks. Additionally, capturing fleeting little good ideas before they run away.
4.5: I forgot to label it, but directly under my whiteboard is my printer/scanner/copier. Very necessary. I don't need an awesome scanner for my purposes, so a cheap-o one works just fine, and a copier is extremely useful for keeping track of any personal checks I receive in payment for my drawings.
8: Exterior Hard Drive. As I've had to wipe my computer twice in two months, I'm gonna go ahead and call this necessary too. I'm set up so that the art files on my computer automatically copy to the hard drive at 3am every day, so in the advent of unexpected system shutdown, I won't lose everything.
9: Noise cancelling headphones. Less necessary now than when I lived in an apartment with really shitty noise insulation, but I've learned I work best with audio. Specifically recorded books. A telivision also works, the point is that I work better when the constantly spinning, yammering, talking part of my brain is otherwise engaged.
10: A blank wall.