This is a good time to go into "tribal" niches where the "herd' hangs out because those niches will never disappear, even in a recession. The biggies include weight loss, dating, making money, sex, etc. Within all of those if you drill down enough with your keywords and you do some brainstorming you'll still be able to find entry points - sometimes a combination of unexploited keyphrases, sometimes a product name or product type. I say stick with these larger trends if you want steady income in this economy - but drill down to find an entry point that you can dominate.
Dan