There are several sites in my feed reader that are not using favicons. It makes it difficult to distinguish you from the rest of the pack.

Please, go get thyself a favicon!

If you need to generate one, pick a small picture that has good definition, and feed it through this program that can generate favicons from photos. It’s so simple, you have no excuse.

Also from the same site, you can make sure your favicon validates so that browsers and feed readers can find and use it.