You can also change the width each product takes, by editing the calculation in product_listing.php or by specifying it in the stylesheet, and not have to install CDP if you don't need all of its dividers. It's a matter of taste...
agile4 - You will get "add to cart" if the product has no attributes; if there are attributes, then a choice has to be made in the product info page before it can be added. Downloads use attributes, and even if there is only one choice, it still needs to go to the info page.
You should be able to hide those links with your stylesheet; I am away from my reference copies of files now so can't tell you which rules to use.You may be able to get the increased spacing between rows by adding margin-top to .centerBoxContentsProducts {}