There are two ways to solve problems when building a website. One is to find a specific tool for each problem. The other is to find and thoroughly understand how to use just a few very powerful, very general tools.
When building a site using Drupal, you can go either route ("there's a module for that").
I prefer the second option, because it lets you invent instead of just employ solutions, so here is a list of four tools that can solve 90 percent of your problems.
- CCK ("Content Construction Kit"). In seconds you can create a new type of content with special fields. They could be text fields, URLs, references to other pieces of content or to users. They could be geocoding references used to generate maps. They could be images or videos. They could be values to generate an embedded chart. Want to make a directory? No coding required.
- Panels. Once you have content and some list display components, you're going to want to mix and match them on pages with complicated layouts. Panels lets you do that. Replace that blog-like page with something more refined.
- Your brain. Ain't nothing like it. The human brain can see abstractions. Once you master CCK, Views and Panels, you'll discover you've been doing it wrong: instead of 99 special-purpose Views, create three or four with variant displays, and learn to pass arguments to refine their behavior.
There are lots of other toys in the toybox, f course, and if you just grabbed the top dozen modules at http://drupal.org/project/modules you'd be well served. But I'd start with these four, because when the question turns to "how can I ...?" the answer in 9 cases out of 10 is "CCK, Views, Panels, and your noodle."