The site didn't have troublesome extensions. It had a template which wasn't that spectaculair anymore. So upgrading shouldn't be too much trouble, and I figured it was faster to create a brand new look than updating the current template.
- Backed up the site.
- Installed the migrator in joomla 1.0.
- Created a joomla 1.5 directory, clean install of 1.5.25, loading the migrator script.
- Checked the new site, all data was there. No worries about module positions, messed up menus....
- Created a joomla 2.5 directory.
- Installed the brand new joomla 2.5.1.
- Installed the SP Upgrade extension and import from 1.5.
- Fixed menus, article settings, module positions...
- Installed a new template, made layout adjustment.
- Installed Rocket Gallery for displaying the pictures and created slideshow modules.
- Moved the 1.o site down, the 2.5 up and removed the 1.5-in-between-thingie. And done.
I'm getting faster at this already.
So here's the new look: