I use drupal and I am not a programmer. I am actually learning PHP using by using drupal. I have tried Joomla several times, and have always gone back to drupal (80% of my sites are made in drupal, the other 20% is Wordpress). I have also tried Wordpress, and have only good things to say about it.
The pros of drupal:
- Cleaner, most available modules are completely free, no strings attached.
- Very stable, and very well thought
- A very large amount of modules that you can combine to make many different types of sites, more flexibility
- Use this if you want to make a site that you will develop over time... if you are going to stay with your site and develop it, then Drupal is your choice
The pros of Joomla:
- Easier to theme
- Better response as far as support from other members
- If you want to develop something that looks cool, and has functionality off the bat, then use Joomla
The pros of Wordpress:
- Easier to work with, stable
- Many modules
- More themes available
- Use wordpress if your site is going to be mainly a blogging site
Of course, this is my own point of view.