I like eobet's the best, the one ykhwong is using in his latest build where each letter is a different bright color. It's simple but colorful. It's easy to spot even when small. The colors and style just leave me with a good impression of DOSBox. It says "Even though it's for old games, DOSBox itself is new and vibrant".
The ChaosFish one is OK, the one used in Gulikoza's latest build with the gold and rust color scheme in a box shape. But relative to eobet's, it just plain and doesn't stand out.
The funniest ones are static's actual DOS-in-a-box theme, which is actually kind of cool, and Tabris's liquid refreshment theme.
For myself, I am hoping to make one with a naked picture of Scarlett Johansson or Jessica Alba. But alas, I have no drawing tools or skill, and I'm not sure they scale down very well. So I'll just use eobet's for now.
By the way, in ykhwong's build, the Status Window has the eobet icon in the upper left, but the main DOSBox window doesn't. How does one get the icon in the main window?
One last thing, I agree with one of the posts about the Z: prompt and Novell. When I first started up DOSBox, I thought "A Z: prompt? Just like Novell".