alika - 5:30 pm on Feb 27, 2012 (gmt 0)
It is incredibly important to back up everything - files, databases, etc. - before you install an ecommerce plugin. It's a major plugin, and you just never know how your blog will react to this new plugin
I just installed wp ecommerce on a site with contents. It broke all my pages and posts. The URLs stopped rendering. My posts showed only if I use the Wordpress default templates, but even then the posts showed up as one long continuous blog in every post URL
I had to put up a backup of the whole site to remove everything. Deleting the plugin did not remove its tables, so you really have to erase everything
From my experience, a separate install of an ecommerce site will be a very good approach. There's too much at stake if you mix it with your blog content.
If the site is just an ecommerce site, that would be ok. But if it has a blog and an ecommerce component, I'd just put them in different installs.