Welcome to WebmasterWorld, joempie. Your dilemma isn't all that uncommon - some topics lend themselves to making money, while others take some work.
Adsense is certainly worth a try. You may be able to get an idea of the demand related to your topic by doing some Google searches and checking out the Adwords ads. You can also use Overture to check bid prices there. If nobody is bidding on related keywords, or if the ads seem weakly related, your potential profit is almost certainly lower.
Working CPM deals for banners or other ads might be viable in a very specialized topic. Presumably, there are vendors who would like to expose their products to your target audience.
You might also try some different affiliate links - get creative, and go beyond your special interest and look at demographics, common interests, etc.
To get advertising (or affiliate) ideas, pick up a magazine related to your topic. See who the advertisers are. Those advertisers, and their competitors, are quite probably interested in your visitors.
Good luck, and be sure to let us know what works for you.