Drupal is one of the more powerful, open source Content Management Systems (CMS) out there right now. If the right solution for you is a Drupal CMS, your next step is to find a good Drupal developer. This may be difficult if you don't know what questions to ask. Here is my run down of skills a good Drupal developer should have (and questions you can ask your developer).
Mastery of Views
Most Drupalites will agree that Views is probably the most powerful module (thanks Merlin). It's certainly one of the most useful! You will want to make sure your developer knows more than the basics, but also knows how to use Arguments, Relationships, View Styles and Exposed Filters.
Proper use of Taxonomy
Taxonomy is a core Drupal feature that allows you to tag (classify and organize) your content. It's important to get this right the first time because it's very difficult to change later on. Your developer should have a good sense of when Taxonomy is necessary, how to treat the terms so when and if it they are needed throughout your site, they are set up properly. Your developer should also have a good knowledge of some of the third party modules that extend Taxonomy.
Knows How to Create Custom Themes
Quite likely, you are going to want a unique design layout that suits your specific website and not a generic template. In Drupal, this is called a "theme". Your developer should have a thorough knowledge of proper theming conventions when making a custom theme.
Knows How to Theme .tpl.php Files
Drupal also features a powerful way to style some pages differently from others. If you want any control over the look of your website, your developer should know how to style template files to suit your needs.
Uses Appropriate Modules
A module is a set of files that give added functionality to your website. Your developer should be familiar with some of the basics like Url Alias and Pathauto (used mostly for search engines and Twitter-friendly URLs), Nodewords and other SEO modules, CCK, CAPTCHA, etc.
Knows How to Choose Modules
Your developer should know what to look for when choosing modules for your specific requirements. Is it well-maintained? How many websites use it? Is it still in development? Is there a better solution?
Knows PHP and MySQL
Drupal is built using PHP (a programming language) and MySQL (a database system). If a module has not already been written for your specific requirements, your developer may need to write a custom module in PHP. If you ever need to recover data, it's useful if your developer is familiar with MySQL and databases.
Understands How to Implement Cron
I've actually run across Drupal websites that aren't running cron, which means nothing is being updated. Make sure your developer understands the importance of setting up a cron job.