Most Competitive Niches

What do you think are the most competitive niches to try and compete in online? Like, it is hardly worth trying since the competition is so fierce.
Today I booked an air travel ticket and was in awe as to the sophistication of the ticket booking and cost comparison sites.
So I think air flight tickets, and maybe car insurance would be the most difficult niches to compete in.
Your thoughts …

See original post by mareks12