searching through the code for places where a round( $xxx, 2) is done I get a lot of results. For example in \Mage\Core\Model\Store.php's function roundPrice. At least this one and another one in a template file cause rounding errors (i.e. price display 399,99 vs. 400) in my shop. Why are all these rounding to 2 decimal place done if it seems that internally 4 places are expected and mostly used? Changing the places to 4 in Store->roundPrice seems to fix most problems. Removing the rounding in the template fixed the display in the product list view.
I searched the code for 22.214.171.124 community edition.