My own site uses Drupal, it's great. Here's a short list of why you should go with Drupal:
1) It's Open Source.
2) Drupal may not look as pretty as some other CMS programs, but it's as solid as a rock. The sourcecode is well written and it's easy to track down problems or customize.
4) Drupal's admin interface is intuitive and simple to learn. The modules are easy to install.
5) Google likes Drupal. (Drupal's unique taxonomy makes it simple for Googlebot to find anything, you'll be amazed at how much Google will bless your site.
There are other reasons, but that's the short version.
I strongly suggest you experiment with different CMS programs first here:
http://www.opensourcecms.com