No money really in blogging, unless you own a network or are a complete blogging whore/pro like John Chow. AdSense pays shit and if you run any other ad network the Goog will whack your PR and drop you from search results.

You're right on about affiliates, I'd combine your idea with my suggestion, start a blog and instead of running AdSense use affiliate links. Remember the more focused your niche is the better.