Which CMS to use for E commerce ?

Hi

I have a friend who has an existing website, which was built using BT hosting templates. He needs to add an online shop, that can deal with around 300 products some in several colours, and will work with his existing merchant account, what would you suggest using?

The key is the design needs to be the same as the existing website, just with the shopping basket elements added to the sidebar. Ideally this will be a CMS that you can add E commerce too, rather than say Os Commerce and a E commerce type 3 column structure.

I have managed to replicate the design fairly easily with WP and added the WP-E commerce plugin's/modules, however I have been told and read that WP isn't really the best thing to use for selling online as its limited. If you have used WP as an E commerce setup and it works well please let me know.

So anyway, my friends isn't wonderful on computers and will need to run this after I've done the setup, so it needs to be fairly easy to run, and I believe that Magenta though great is very difficult to run.

I think once the site has been setup and only things that will need changing are products details, so know actually structural issues/alterations ongoing, hopefully. I have been told that there are issues with Joomla and Virtue cart, that it has many bugs, do people find this to be the case?

He may well need to add a blog at some point so as mentioned a stand alone E commerce package, isn't really the route he wants to take.

Drupal, Joomla, Magenta, WP or other ?

Any ideas?

Thanks

Ash