It looks great on my 1024×768 screen. But when used with a higher resolution monitor, the background image will continue to float right beyond the bounds of the WordPress boundary. One of my readers says it looks a little weird. ;-)
For the time being, I’ve padded an image and set it to the left.
If you want it to be to the right of the title/tagline, then you need set the image as “center” at appearance > background. You may have to make a few different images and play around with things to get it positioned as you want it.