The recommended approach is to use STSADM -o export to export the site and then to use STSADM -o import to re-import the site afterwards. Alternatively you could set up a content deployment job to deploy the content from one environment to another.
If you do decide to use STSADM -o import to create a new site I recommend that you…
1. Create the Web App in Central Administration.
2. Use STSADM -o createsite to create a blank site collection in the new web application.
3. Use STSADM -o import to import the exported site into the blank site.