If I'm understanding you correctly, then no, that isn't something that is as easily achieved with divs as it is with table cells. As far as content goes, it doesn't matter - the side divs will be as high as they need to be to accommodate their content. It matters visually though, if you want the appearance of side columns extending down equally with your middle column. I find this easily "faked" with a background image that repeats vertically.

Here is a quick example: there are three columns with one containing div around all of them (which is outlined in red on the screenshot). The column div that's outlined in purple stops before the div on the left does, but because the containing div has a repeated bg, it appears to keep going. Of course this requires fixed-width columns so you can plan your bg image appropriately. A liquid layout would need a different approach.