I can second Wordpress, not used any store plugins as I'm going to be using nopCommerce for mine, but Wordpress is fairly simple to set up and use for the uninitiated.
You can create very professional looking sites really simply and as it has all the Search Engine Optimisation stuff built in under the hood, you don't need to be a genius to rank well on google.
Also, perhaps most importantly, it is updated fairly regularly to make sure your site stays secure.
and it's free!
http://wordpress.com/