Hey,
I’m having some issues with the default template from wordpress (twentyten) which I have modified.
I am trying to extend the right column 100% height and have the footer sit below this. Instead the the right column is extended down the page to a point and the footer sits below this.
The content div does not seem to be pushing the container div all the way down.
Any idea what I am missing?
Sorry we missed your post but it looks like you found the right answer anyway. 
The only real way to have 100% high elements is to fake it in some manner (e.g. with faux columns, wide borders or with negative margin tricks etc.(or use the display:table properties for modern browsers).
In case anyone is searching and finds my post - by chance I found lots of helpfuf info in this thread (that I didn’t find by searching).
Basically - what I was trying just isn’t possible. However, the ‘effect’ can be achieved by clever use of the css ‘border’ property.
Hope it helps.