The most important thing is to choose something you enjoy and something that you can focus on for a very long time. If you are looking to build a following, you will need to write, write and write more. Your passion for the topic will come out in your writing, so it is important you choose something you believe in and enjoy.
If you are writing a separate blog, sometimes it is easier to focus on one niche to build the following. If you are planning to write this on hubpages, you can easily write about several different topics which is the beauty of this platform.
If you want the blog to be long-standing, I wouldn't recommend writing any dated content because people will stop searching for it which will result in a decrease of audience and $$. Also - the popular topics are sometimes the hardest to break into with a new blog. Sometimes focusing on a smaller off-topic niche will build a quality audience quicker.
So - while I can't just tell you which direction you should go, this may give you an idea of what you want to do moving forward. Good luck!