I've been using San Kloud ever since I started my blog in May.
For me, a theme must have the following qualities:
1- Text that is legible for readers of all ages. That means no white text on a black background.
2- A custom header option (or a unique header on a theme that few people use).
3- Text and menus in boxes, separated from the background image, and preferably with a lot of the image showing. This lets me have a more eye-popping look without compromising readability.
I actually just wrote about happiness and change on my blog: