Lately it seems that more and more people have gotten into the habit of using Blog Banners which they whip up themselves or have other people do.
- Start with the highest quality artwork you can.
- Less is more.
- Work within a program that allows you to work with vector graphics instead of raster graphics. (For example, Inkscape instead of Photoshop.)
Not perfect, but not bad. Design-wise it could use some help.