bigcommerce is the best. i've been with oscommerce, magento, shopify, magentoGo, volusion, opencart, and even prestashop. zencart is a variation of oscommerce. I would rule everything out, if your not going to go with BigCommerce, go with Magento (but theres enormous costs that most newbies don't realize) trust me, i've experienced it. I do offer ecommerce services, but PM for more details, I'm not trying to sell you anything, I just want to give you a advice that no one gave me
My recommendation is PHP, it is the most popular and widely used for shopping carts. With the help of Interspire Shopping Cart (Free version), you will have it ready in seconds. To get this, please visit http://www.iscexperts.com/viewtopic.php?f=2&t=11 feel free to report any bug or request a feature.
EasyStoreHosting is best Online E-Commerce Store creation software. I have tried it, and it genuinely works. The best thing is that provide "technical support service" free of cost. So you have to do anything by yourself, just shoot a mail to them, they will do it for you.