There really is no "one layout" for a link list. In fact, its really up to you to decide how you would like it to be and will depend on what your link list will offer the surfer. The key though is to make it so that as soon as a surfer comes into your site, they can easily see where to go to find what they are looking for, or at least give them options to choose from. Nothing should be hard to find and site navigation is definitely important. In simple terms, you should at least have the basics:
1. Category list of niches
2. the ability to easily go to another category from the one you are in
3. the ability to provide easy to find navigation to any other section
For the actual site listings themselves, you will definitely want to have the Site Title, Description, and of course the Link to the site. It is at the descretion how a webmaster wants to list sites: Alphabetically, by date of submission, by hits, by votes, or a combination (if your script allows it).
Not sure if this helps or not, but I am sure the others will offer more
