My blog has pretty much looked the same for the last 4 years. I have been using the Atahualpa-theme, which is very customizable, and which I have been very satisfied with. But everything comes to an end, and I felt like trying on something new.
After searching around on the web, I found the theme Subway by yootheme. It has a metro-look and feel to it. After looking at the demo-page I decided to go for it. I think it looks pretty, but it is harder to customize and work with than my previous theme.