The ‘margin-bottom’ on ‘#home-content’ collapses through the bottom of the ‘#page-content’ on IE, whereas on other browsers it correctly sits above the floats just after ‘#home-content’ instead.
Margin-collapsing is quite hard to get right, especially given IE's bugs, so it's often best avoided if you can (using padding-top/bottom instead).
In any case I would strongly advise you not to try to make your page heights an exact number of pixels like on this page. Any change in font settings/size will break it badly; for example if I zoom the text size up a bit half the text falls out of its containers, making the page entirely unusable.