If you want people to enjoy the list for its own sake, pack it with useful content. Dispense wisdom that folks can't get elsewhere, and that will make them want to stay subscribed. For an announcement list, it's better to send out fatter messages less often. Resist the temptation to include too much advertising, and never put an ad at the beginning of a message - people will assume it's spam. As our friends at the search engines will tell you, a resource that has links to lots of other resources will attract more visitors than will straight content.
Many mailing lists consist of nothing but links.
If the list itself is the point of the exercise, then there's no reason not to include links to whatever appropriate resources you can find. If you simply keep an eye out for new links of interest to your audience, you can make up quite a useful little weekly or monthly list with comparatively little effort. If the point of your list is to generate traffic to your site, you should approach things a little differently. The name of the game is to feature scads of links to your own site, and few or none to other sites. Click on over to the site to find out how.