What about a more general search like widgets? Would a surfer clicking an ad expect to be landed on a product page, or a review page or an article describing all of the different type of widgets with appropriate links or some other type of page?
What I am attempting to do is find what type of landing page is appropriate when a search is not for a specific product, but for a type or category of product.
If it's 'digital camera' don't take them to 'Olympus model 3005a' page, take them to your main page for digital cameras.
If you only sell one brand of camera, then say so in your ad, and take them to that brand page.
With more general keywords, a lot of testing can be done that will help you over time (if you're measuring results based on landing pages). You can try a 'Featured Cameras' page with links to those cameras and then a link to your main camera page.
You can take them to a search result page on your site that is prepopulated with their search term, but gives them the option to refine their search on that page.
For these keywords, use your imagination, and then split test the results to see which gives you a better ROI & conversion.
With each extra click you will lose a X percentage potential customers..
