Well i mean depending on what you need as in features i have a great shoping system called VirtueMart this does run with joomla but its quick and easy to install maintain and is very user friendly also templates can be downloaded or self created and i do have other E-Commerce
http://www.internetconquorer.com/ind...=38&I temid=1
there are a lot of scripts that do a much more basic system but they are all good
p.s. sorry about the typing i have my baby on my lap lol!