Honestly, I wouldn't worry about it. I couldn't be sure what the top 1% are, but given that addictive substances and pursuits always sell well, I'd guess sex, drugs and gambling are pretty good niches to start with.
You might be far better off finding a merchant in the top 25% of affiliate programmes, related to a topic which you can talk about with some expertise and which has comparatively little competition (so your SEO hurdle is lower and your PPC costs are less).
Which programs fall into the top 25%? That, you'll have to figure out for yourself. (Why? Because nobody else has an interest in seeing their SEO hurdles get higher and their PPC costs increase).
[edited by: ronin at 9:16 pm (utc) on April 24, 2007]