The first major disappointment from my iPad was not being able to post pictures to my Drupal sites. The sites are using CCK, Filefield, and Imagefield. This is a great solution for any computer and OS except that iOS devices don't have a way to browse files so you can't upload them.
I just discovered Filefield Sources http://drupal.org/project/filefield_sources. It extends filefield, allowing a URL to be inserted so you can download images from the web directly to your site.
I had an interesting request on a Drupal site that I'm working on. I've created a view with a list of names that had a significant date and some other information. My original understanding was that we needed the list grouped by year of the significant date listed in descending order by the significant date. This was easily done using Views 2 right out of the box.
A few months ago, I needed to bring in an XML feed from another provider. This wasn't a RSS feed that I could use feeds API on but an XML with fields related to lake levels, etc. In the past, I had used the built in simplexml features in PHP 5 to do this job. The problems I had in the past were that the feed would go down for hours to days at a time. This would only serve to break my site. It seems that every time I edited my code to compensate for an error caused by the buggy feed the next time it would cause a different error.
For anyone who is having problems getting the Twitter module to authenticate with their account you'll need the Oath 2.02 module and to upgrade Twitter to 3.0-beta2. Look at #58 on for a good tutorial on how to do this. http://drupal.org/node/404470#comment-3405168