I used to use the Google XML Sitemaps plugin by Arne Brachhold for SEO. Then a friend got me to try out WordPress SEO By Joost de Valk and it seemed like a good SEO tool until I noticed today that it had duplicated my site name in the HTML header’s TITLE tag. After not finding any easy way to turn off that “feature” I just disabled the plugin and switched back to the Google XML Sitemaps plugin I used before. I works well and has all the features in need, plus it’s easy to configure, easy to use, has really good support documentation.

the Google XML Sitemaps plugin