I've rebuilt kief.com using new software, a PHP-based content management system called Drupal. I didn't have any particular problem with my old software, Movable Type, I changed because I wanted to learn how Drupal works. Movable Type is designed for use in a weblog format, with backwards-chronological list of posts, which is fine for kief.com. But I've been wanting to create a new website which will have a more complicated format which I think Drupal is well-suited for.
The choice of Drupal is significant for me in that it is written using a language/technology I haven't worked with before, PHP. This isn't out of any desire to learn PHP, I would actually prefer to use Java, which is what I work with professionally. However, I've been farting around with Java-based content management for years, and it's actually been a big obstacle for me starting the kind of website I would like to have, for several reasons.
Part of the reason I haven't been able to get a Java-based, content/community-oriented website going is exactly because I am a Java programmer. Whenever I have started on one of these projects in the past, I inevitably get bogged down fiddling with the software, and usually end up wanting to write big chunks of the system myself. The software is never quite done the way I want it, so I spend all my time coding. Since I don't have gobs of free time for this kind of project, I never get anywhere with it. Since the projects I want to do are usually building websites rather than writing software, this is counter-productive.
This problem is exacerbated by the state of Java content management systems. There are plenty of frameworks out there that can be used to build a content-oriented site, but nothing that you can just drop into place and start using. I particularly like JPublish, and also Daisy, but either one (or both) would take a lot of work to get going with.
The reason I've started playing with Drupal is that it's oriented towards the type of site I would like to start - mixing community (blogs, forums, comments), and old-style traditional content. It has some fairly large gaps - it doesn't handle images very nicely yet, and it seems awkward to create pages that collect different types of content in useful ways, such as section hubs and monthly archives. But it's technical architecture looks very clean, solid, and extensible, and there is plenty of activity with modules that can do the kinds of things I'm interested in.
Of course none of this actually guarantees I will get a new site underway any time soon, there is still plenty of work to do.