Re: Simple (?) I.E. and FireFox Problem
You’ve floated the hot tags div (#front-page #hottags), but the hot tags div is not that tall so it doesn’t “reach down” to where the Forums table is. Thus, the Forums h2 and the Forums table appear flush with the left border (instead of being pushed to the right by a hottags div, as is the first h2 and table).
You could wrap the two tables (and their h2s) in the main area inside a parent div to prevent this.