I meant when I DO NOT LOG IN, that means when other look at the blog. There is definitely a missing </style> missing. This happened with two people and with a bunch of different browsers.
I will try the wp_footer(); // but this does not seem to be related. The missing tag seems to be in the header.php file.
It was happening just before the 3.1 update. So I updated, and it behaves the same. I guess that does not help much, sorry ??