I have gone the many niche mini-site route which has performed fairly well for me so far. However I agree that if you can create both and interlink it is a great option. Only trouble with having a huge number of sites is getting the time and resources to promote them all.
Both have pros and cons. I prefer multiple sites because if one gets black listed you are sunk. Tip: Network all your sites into one.
In my opinion, picking a niche market which you are very passionate about and then creating an authority type site around it is the way to go. This is something which I am currently trying to do with my weight loss/health related website. It's all about your preferences through. Do you want to invest a ton of time into one website or do you want to diversify? Like I said, I prefer creating one larger site as opposed to many but that is mainly because I like my website's niche market.