I used drupal for my site http://thestasis.com and another one within my organisation-intranet. Later as I learnt and realised the scaling potential and usability, I felt Drupal was better for an enterprise and may be wordpress for personal blogs. I see competition for Drupal from SharePoint. Don't know much about SharePoint but enterprises tend to stick more to vendor provided solutions than Open Source.

Having said that, I upgraded my company intranet site to Drupal 6, and my personal site to wordpress. One big reason was the Wordpress2.5 dashboard that allows me to see at a glance what all's been happening. Drupal badly needs that one.

• So, Drupal6 needs a dashboard right after an admin logs in.
• Though Drupal has a lot of modules, we need to have more built in. I only use 3 modules with WP but about 15-20 with Drupal.
• Drupal needs a dose of Ajax. Though WP too lacks on that front
• The Drupal logo (missing in v5) is a welcome and powerful marketing/advertiting enhancement. WP has been doing it all through.
• We need a pleasant Web 2.0 kinda default theme that makes the site look light and nice.

While I have more suggestions (read stinkers) for WP, I personally find Drupal to be more suited for enterprise level scalability and customisation. Something that works right out of the box is WP2.5