I had been putting off upgrading Joomla! from 1.5 to 2.5.9 on Lyn's site(laf-art.com) and chakonari. The main reason being that in addition to a custom template, I had modified core files for Lyn's site's layout - something I decided to avoid as soon as I realised the cons - but my webhost updated php on their servers (which was actually a good thing) which resulted in error messages related to the code being outdated appearing throughout the sites. So I was forced to make the move.
Due to the amount of content Lyn had on the old site, I couldn't just start fresh as I'm doing with chakonari. Fortunately I found a tool to export/import articles as xml files: J2XML and I didn't have to do much work on the template either. I did have to copy the translations manually though.
Now it's just a matter of deciding what extensions I'm going to use here - some of my favourites don't work with 2.5.9 - and working on the layout. I went live with what I had done so far as I know it will push me to get it finished: "Hey, people can see this. Clean it up!" :P
On a related note: Using Firefox as a dev tool almost takes the fun out of designing a layout as it shows instant results - unlike using notepad to code CSS. But I'm only saying this because in this case it doesn't matter if something is going to take me a few minutes or an hour. In any event, looks like I'm in for a few weeks of dreaming of CSS code again. :D