During the last days I've been working on making KWin's effects configurable from a KConfig module. Until now, if you wanted to enable/disable an effect, your only possibility was using DBus. DBus support is still there of course, but now you can alternatively use KPluginSelector widget (which got a nice makeover thanks to Rafael Fernandez Lopez aka ereslibre) which shows up among other KWin config modules when you RMB on window title and choose "Configure Window Behaviour".
Internally, KWin effects are now services, so we use ksycoca to get a list of them as well as find out in which library a given effect is. This made the code tiny bit simpler and might also result in some performance improvement.
Additionally, effects can now have their own config modules as well, so you can fine-tune them to your personal preference. ATM only two effects (shadow and presentwindows) are configurable, but more will certainly follow.
I wanted to make a video of config possibilites, but it evolved into a much longer video which briefly shows you how to enable compositing and how to choose and configure effects. It also shows some of the (IMHO) more important effects. The 6-minute video can be found at YouTube.
Update: there's also 16mb .avi with slightly better quality, but it's server could be slower than YouTube.
Finally, it looks like I've been added to Planet KDE :-)
If you're interested in more KWin stuff, you might want to check out my previous post as well.