For experts.

OK, the usual suspects... IE.

<< link removed >>

Check the space between the #buttonsbar and the #sidebar.
I've managed to remove it from the #header by adding the logo as <img> not
from CSS, thus removing the height property*.

*The broken part is created from the height property in general. I still have it on the #buttonsbar.
How would one fix this?

try using
display:inline;

on the #sidebar.

Also note your page is breaking at smaller widths.

What about setting this as a background image on the containing div?

something like this:

.main #container
{
width: 82%;
margin: 0 auto;
text-align: left;
background:#080808 url(../images/people.gif) no-repeat top right;
height:500px;
}

note I just put that height on there so you can see the image.