The Joomla! Extensions Directory ™

I would say that this extension is best of all the available ones for e-commerce. I will start with the pros and cons of this extension. I wont be listing up the features as those can be found from their site:

Pros:
* Flexibility in template selection, you can assign each product, category etc different templates.
* Support from the forum, got quick reply from their team.
* Personally, Without User Registration was the feature I wanted and I got it right with this one.
* Promotional emails can be triggered just from the shop with product images etc working as tags, so provides complete solution.
* If you are shipping different size products, then this shop would be handy because it takes into account sizes and volumes to calculate the shipping.

Cons:
* There are many configuration options, but if you just dont touch them unless you need, its fine. Personally, I enabled pre-order while playing and got stock-room down. But disabling did a trick.
* Require basic html knowledge for setting up the templates right.
* Backend UI needs to be bit better (Though the later version is far better then previous ones).

Overall am satisfied with the product as well as support, but just a piece of advice, you need to bit patient to find what you want this shop to do.

My Two Cents.