I would aim to make a website your own interests, trust me, I recently started a dance music blog because im one huge fan of dance music, and it helps keep me really on the ball with all the newest tracks but even with such a huge passion I struggle to find things to write about and sometimes lose interest.
If your considering starting a website based on something "trendy" of "popular" and for that reason only so you can make abit of money then u really dont recommend it. You will burn out quickly and thats never good.
Aim to do something you love. And most importantly stick at it. I've been trying to get my blog of the ground since ... oh about june last year, and since then I've had numerous servers go down on me for weeks at a time, lost everything I had written a few times, and more, its mainly my fault but its heart breaking when it happens and if your site is offline for a few weeks u lose all your readers. Its only just recently after having my blog up and writting lots since december.. then just recently starting to advertise that my traffic has began to increase. In the last 2 weeks my site traffic has increased from average of 4 ppl to 40-60 visits a day.
Its the straight and norrow and you will fall off many times.. gl with it all