The single best shopping cart OTS program is...?

[IAmAllanShore]

Question is in the title :tu:
I am trying to find the single best off-the-shelf shopping cart program for a tangible goods e-commerce website. Bonus points if the shopping cart integrates with a well-known merchant processor .
So, let's pretend I am selling "marbles." As the buyer, since I have undoubtedly lost my marbles, I go to AllansMarbles.com (Not the real site ) and want to be able to browse page to page, adding things to my shopping cart as I go (Much like the Amazon.com "feel" to things.) and when I am ready be able to checkout without it feeling like a crappy FleeBay auction (Multiple layers of "checkout" that don't keep you at the same site, etc.).
Rep and $NP for advice, or just the feeling that you were helping out someone who made the mistake in the past of cheaping-out on the checkout system, and is now trying to correct that error :notme:
Muchas gracias para todos,
-Allan :gl:

(And yes, ccNow was the original system I used - but they charge 5% and require the customer to go off-site, which isn't going to cut it ).

 

[DomainReseller]

Try the following:

OScommerce (http://www.oscommerce.com)
CubeCart (http://www.cubecart.com)
Agora Shopping Cart (http://www.agoracart.com)
Zen Cart (http://www.zen-cart.com)

 

[DotnetKris]

http://www.magentocommerce.com/