My choice of CMS is Drupal. It's an open source platform built for all sorts of sites from simpler personal blogs to more complexed sites. Because I know people seem to think other CMS' are better, I decided to list some reasons why I think Drupal is the best around.
A couple of years ago I tried a bunch of different platforms in order to find the best one for my needs. Before this I had mostly been building websites and some simple database or text file based content managements from scratch. Joomla seemed promising, but at the time it wasn't flexible enough and for some reason I found WordPress too difficult to implement. Drupal I got immediately. Of course since then all these platforms have changed and developed. Drupal is now way better than it was.
Drupal is flexible. It can be used for very simple sites as well as building something more sophisticated, like a full e-commerce site. There are thousands of modules available and more can be built if needed. A Drupal site is fully customizable, but you can get quite far with the basic installation as well. For a geek like myself Drupal is a great platform to tinker around as much as I can. Or as little as I want to.
Add-on modules include Views and Content Construction Kit (CCK) which can be used in imaginative ways for creating almost anything. I find new ways to utilize Views and CCK all the time.
Theming Drupal can be made difficult... Or very very easy. There are loads of contributed themes to choose from or you can build one from scratch. Starter themes, such as Zen and Fusion are there to help to get the theming on the way. Even more advanced theme frameworks are available, likes of AdaptiveTheme.
Making a Drupal site content easy to update isn't really that difficult. With different modules, including Views and CCK mentioned above, updating can be made extremely smooth for even less experienced web user. I recommend using one of the administration themes for (surprise surprise) administration and content editing. For instance RootCandy and my current favorite Seven are great admin themes.
And what does Drupal cost? Well, nothing. Drupal is a free open source content management system. The contributed themes and modules are free. Of course some third party plugins and themes may cost some, but that's the same thing with any other CMS.
If you want to see what can be done with Drupal and creativity, check out the interesting and cool examples on Drupal Museum and drupal sites network. Help with your Drupal is around the web. For those who like their instructions in video form DrupalCamp24x7 is filled with video tutorials (and is a good looking site as well).
Suomeksi (In Finnish):
Syy miksi käytän Drupalia on se, että se on helppo ja joustava sisällönhallintajärjestelmä. Drupalilla voi rakentaa monenlaisia sivustoja, simppeleistä blogeista monimutkaisempiin verkkokauppoihin. Drupalin saa myös muokattua sellaiseksi, että sen sisällön päivittäminen on yksinkertaista jopa vähemmän kokeneelle netin käyttäjälle. Ja Drupal on tietenkin ilmainen. Jos haluat nähdä mitä Drupalin ja luovuuden avulla saa aikaan, tsekkaa esimerkkejä sivustoilta Drupal Museum ja drupal sites network.
