http://drupal.org/ is very popular. Many people also use Wordpress - http://wordpress.org. Also try googling "simple cms".

The answer will obviously be dependent on the requirements of the software and the capabilities of your server.

Perch is excellent for small sites.

At its very simplest, Perch allows you to replace static content in an HTML file with placeholders. A simple GUI then allows you to edit those placeholder values for individual pages. So, for example, if you have a file containing this chunk of markup:

<h1>My site</h1>

you can change that to:

<h1><?php perch_content( Main heading ); ?></h1>

and you ll then be able to edit Main heading through the GUI. Most CMS apps work in a similar way, but Perch is the first I ve come across that does very little else, which is a huge plus for small projects.

I haven t used Perch for a while, and I m sure they ve added some features since I last did, but I d still recommend you give it a try. It s cheap, too.

I think couchcms is a pretty good open source alternative to the likes of cushycms and perch

I recommend cushy http://www.cushycms.com/

You should also check out opensourcecms.com. You can try out various cms s there until you find one you like.

For a five-page website, Drupal is probably overkill; I d say Wordpress is good enough (just define a page for each page of the website, copy and paste your content, choose a theme, and you re done). (You would want to either use the blogging features of WP to take full advantage of it, though.)

If for some reason you really want to try out Drupal but don t want to invest a lot of time into figuring it out (it does take some ... well, a lot ... of time to figure out right out of the box), and you re not in a big hurry, you can wait a bit until it s possible to try out the new Drupal Gardens hosted CMS system (currently in beta). (You need a beta key to try it. Sign up for the beta on the site and then wait for your key.)

Since your most likely a programmer I would recommend github s very own Jekyll:

Here are some sites powered by it: https://github.com/mojombo/jekyll/wiki/sites

As a bonus you can use Github to provide you free hosting (your site will be a public repository that only you can edit).

Have you tried using mut8? They have pretty alright features.

http://mut8.me