Which is more ideal: using one domain or multiple ones to brand a product?

Hey guys!

I'm in the midst of starting a business in which I'm writing, recording, and selling guided meditations. These meditations will be on varied subjects including weight loss, sex and relationships, healing from illness, general relaxation, etc, etc.

I don't want to put all the recordings on the same site because different meditations are going to attract people with different needs. I also think it would be inappropriate to have, say, meditations about healing from cancer on the same site as meditations about enhancing your experiences in the bedroom.

So, I was thinking of using a separate domain for each--yet each domain would be similar. As an example, I could use domains like VisionHealing.com, VisionConfidence.com, VisionWealth.com, etc, etc and create a "Vision" brand.

(I'm not actually using "Vision". I have another word in mind. I'm just using these domains as examples.)

Each site would have links to the other sites and I'd also include links to the sites within blog posts. In a sense, I'd be creating a blog network.

Multiple domains and multiple sites keeps things separate, but it also brings with it much more work to juggle all these sites.

What do you guys think? Is it better to have one domain? Are there many benefits to having more than one domain and site? And is there a way to set things up in which all these Web sites can be managed with ease? Technically, the Web design will be pretty much the same as will the set up of the Web store. It's the idea of doing one blog post per week for multiple sites that freaks me out.

Any thoughts would be greatly appreciated.