there have lot of hot niches in my opinion such as IM, weigh loss, email marketing, financial. English is worldwide, facebook is so popular now
All I can say is that the best niche for Internet Marketing is the one that you have the most knowledge and information about.
latnemele hit it right on the nose. Also, other great niches are niches that solve peoples problems. When people have some sort of condition or problem they want help right then and there. Weight Loss is HUGE but extremely competitive. Seasonal niches are great to and are usually less competitive.
I'm going to say make money online or anything related to Internet and Affiliate Marketing. And those will probably grow daily. Anyone choosing those will probably make some good money if they decide to teach people.
Believe it or not...I have had and sold websites not associated with the evergreen common list of niches and have done pretty decent for myself. I used to go to barnes and noble and sit there reading magazines I normally wouldn't pick up. Then it dawned on me. Publishers would be selling this magazines unless they had a following. So I toyed around with a few niches based of of the common theme from a few magazines and within a week I ad a product and was making $500 a week. I had fun and sold them. But the moral of the story is that there are sub groups of people that have interest in so many different things. There are so many niches out there dying to be exploited...ughmm..."helped" (J/k). Go hunting for weird sh&T one day. I found that geocaching has a big following and even has a magazine, products for their activity both on amazon and ebay...not a lot...but enough to know that they exsist. Niches like this can be blown wide open with a creative mind and drive. Creating products for markets that don't have them yet is the ultimate money maker and one can easier shoot to the top as a guru-master-chief-head-honcho. Just keep your head on a swivel and pay attention to offline activities you'll find that people are so much more than just weight loss, abs, make money online now, gambling and dating. Sorry for the tangent...I needed to get that out. I hope that helps.