After using Drupal once we are definitely converts and will likely make this our CMS of choice for all projects going forward. As this was our first foray into the world of Drupal we had a lot of help from a few key people (whom I'll mention in a follow-up post) that helped us ramp up the learning curve.
We've got a whole host of modules running on the site with a few custom (ahem, *hacks*) that make it all run nice and smooth...
The trickiest part was definitely the e-commerce component and that warrants an entire post (coming soon...) explaining all the twists and turns we followed before finally coming up with a very comprehensive (we think) solution. We used http://www.aMember.com plugged into the Cybersource gateway as we needed to support recurring credit card billing.
I am currently working on a concept project for our community. I used the old aggregator2 and a tag cloud snippet to come up with what is now known in our community as smartcloud.
Web 2.0 web design techniques seem to be taking over. This is a breath of fresh air from the typical three column layouts that are all over the web. Over last weekend I got curious as to how hard it would be to implement some of the Web 2.0 techniques using a CMS. The result was better and easier than I expected.