Nice looking site, reminds me of how a UK Web Designers Forum
looked until very recently.
The Google Insights for Search
tool may provide some inspiration as it helps to reveal what people are seeking online both locally & globally.
See a need , fill a need - Bigweld
Avoid harvesting data from other sites and passing it off as your own (Google really does not like it) but
if you can combine data from two different sources to provide something useful you may have a winner. For instance I'm looking to move house and getting really fed up having to manually find the broadband speed for the area on another site because most real estate agents don't provide it.
Depending where in the world you are a Tourist Information site can yield unexpected traffic, after all if you live in a place then you know it better than any travel writer could ever do. Like who runs the best taxi service, what restaurants the locals avoid for fear of food poisoning.
If you are good with a camera then Photo-Stock site may suit you better, content creation is just a finger click and can be combined with any other regular job while the number of images and visitor traffic builds up.
Controversy also creates forum traffic regardless of the subject with the hugely popular and somewhat heated debate about the 9/11 incidents being a prime example.