When you've got a site with any sizable amount of content, sometimes you'll just want to do a bunch of things to a bunch of stuff. The Views Bulk Operations module provides a powerful extension to Views that allows you to do just this. Awesome stuff.
Drupal 6
12/13/2012
One of the most unnoticed changes from Drupal 6 to Drupal 7 was the inclusion of image handling in core. A typical Drupal 6 setup comprised of CCK and Imagefield to add images to nodes, along with Imagecache to render the image in various sizes. The Drupal 7 core Field and Image modules are for the most part direct replacements for CCK, Imagefield, and Imagecache; however there is a distinct difference worth noting. Preset handling.
11/10/2012
At some point the data you're working with is likely to become complex enough that you'll need to store data for your module in custom tables. Take my advice and let the schema do the tedious work so you can get to more important things--like writing some awesome code for your awesome website.