The homepage of an (mid-size) e-commerce site has only one primary function: to upsell. The rest is secondary.
There are a lot of people that get to the product page, add a product to a cart and then start looking for something else - just in case they find something they like. And one of the places they often check is the home page (sometimes more often than a site map or a catalog listing page).
If you employ typical ppc/affiliate/jv combo marketing for a catalog site, then most of your visitors will enter your site at either category or product pages. And absolute majority of those that add something to the cart will see the cart before they (might) see the home page.
So when you are designing your home page - think of those visitors that added something to a cart, but have not finished their order yet. Selling more to those guys will make you more (extra) money that anything else you might do with your site.
If you can convince someone to get back to the cart and go through with the checkout process - that's good. But if you can convince that someone to add more items to the cart before checking out - that's (much) more profit right there.
HINT: Try not to use static home pages when you can, but have some space that is being linked to the cart and upsells the visitor based on the items he already has in his cart. So if a visitor has added some widget to the cart, and then went to the home page - it would not hurt to display a few related widgets to the one widget that he has in the cart. And not just a list of best-sellers.
Another possibility is to display a picture of that very same widget (that's already in the cart) and a sign like "Buy two and we'll take 10% off."
Think of the psychological effect that would have on the visitor, when he sees a "special" offer for the exact item he really wants.
If you decide to go with the related widgets, then make up a special offer of "the widget in the cart + another related widget=10% off."
There are many different things you could do, but the point is the same.