I thought the link to the existing topic regarding this subject in the feedback forum would have given you all a chance to look, so here we go - the long and short.
its not the main page that is the problem - click on 'commodities' or 'ships' or any of those parts, and you get a thin column, with the text wrapped into a tall thin column down the middle, and a large amount of space to waste.....
Most webpages are set for viewing optimisation at 800x600, or more commonly 1026x768. About 98% of users have that setting, so surfing on 1600x1200 could lead to many sites having many problems - they don't have to cater for everything.
If you maximise the window at that setting, then I am affraid its your choice, and it shouldn't be put onto website makers to try and sort everything out for you - simply put there is a limit where they can accomodate everything! True - using width settings as percentages can remove that, but it still leaves problems with presentation looks etc.
Its almost like the width of the <td> tags or <table> tags are done incorrectly - but its not that simple. The site is in asp, which i know nothing of - so I don't know if its got the equiv of php includes on the pages or not - just don't know