During the last couple of years, I've created a few Joomla websites with Virtuemart as the e-commerce component. Although I struggled a bit to start with, I think it works fine now. I still find the control panels quite cluttered and not exactly intuitive, though. It took a lot of time to get to know all the quirks and oddities (like links that lead to not-yet implemented features...!). After a while, however, I have come to like VirtueMart, and have managed to set up a few quite successful webshops using it.
One of the things I don't like so much is the lack of themes and templates made for Virtuemart. A few weeks ago I was made aware of Yagendoo, a company specializing in templates and extensions for Joomla.
Yagendoo have made a series of templates, extensions and add-ons for Virtuemart. This includes complete Virtuemart template packages, Flypage themes (the actual product page), browse page themes (list pages), Add to Cart buttons, Notice box designs, Thumbnail carts and Availability icons.
The add-ons are very easy to implement in your Virtuemart site. You can download and install a complete theme with all the functions included. Or you can use some of the elements to enhance the built-in theme or any other theme you might have made or installed.
I will try this out when I find the time - I have wanted to improve the design of different elements in my shops for quite a while. I'll report back when I've tested the stuff for a while. In the meantime, head on over to Yagendoo and see what they have to offer yourself.