Perfect example of a computer niche site that's highly popular is PCPartPicker. That site is basically one great big affiliate marketing page, but computer people love it. Why? Because it makes their lives easier. I've used it countless times, I've shared it with my friends and family.
The niche can be highly profitable, but you've got to keep something in mind. These people tend to be knowledgeable, which means they're familiar with google. Googling a bunch of stuff, copying it into a pdf and repackaging it as an Ebook isn't going to fly. You're going to have to put a lot of work into finding (or producing) a quality product that's going to make their lives easier.