The new one I'm trying to use can be seen below.
I've tried using both 1930 x 200 and 1280 x 200 background images. It looks fine on some screen resolutions, but not on others. I've noticed this site's banner always looks great, hugs the screen perfectly no matter what the screen resolution is and they are using XF as well: http://www.reef2reef.com/
So what am I doing wrong?