I'd like to throw this out to everyone who makes money from AdSense and affiliate programs, which is better, an ugly theme (or at least a very plain theme), or an attractive visually appealing theme? There is a vote as well.

I consider an ugly or plain theme one that makes the reader just want to get out of there, or the colours are so bland it becomes hard work reading the page. An attractive design would make best use of fonts and colours to make the reader want to read more.