I've been using WordPress now for about 1 year and I continue to be impressed. It has been the easiest system to install and enhance, it has never let me down and if I need a feature, there's a 99% chance that a plugin exists to do the job.
One of my sites (http://www.ebrington.com) uses WordPress to provide a B&B site along with local news and information. It also integrates with the Amazon web services system to sell books.
After much experimentation, I'm using the following plugins:
GT Tag cloud
Google site maps along with an enhanced version to inform Google news of updates as my site feeds Google news.
Flexible upload for image importing/resizing
Event Calendar to show what's going on now and in future months
and my favourite WeatherIcon showing local weather information
Keep up the good work WordPress team - you're doing a fantastic job.