TLD Linking From Your Own Sites?

This is more a question of curiosity then anything. Ive been doing SEO for a while now and I've made a lot of contacts during that time. Something that ive noticed though is different ones have different opinions. As SEO is no exact method as such and there are some things that are presumed infact Id say most SEO is presumed.

One of these things is linking to your money site from your own third party websites. Some say yes it benefits some say no it doesnt the reasons vary and Im wanting BHW's opinion.

If my main site sells for example watches and is watch.com and I then have 5-10 sites for traffic e.g. watch video sites, autoblogs and other watch related sites such as maybe watch repair tutorials would the links from these sites count as good quality links for my money site?.

All sites are on shared hosting and are all under my name.

Personally I cant see why the links shouldnt count but some lay claim to the whole unique IP thing etc.

A good friend of mine who works with webhosting talk (gets paid business trips etc) firmly believes that unique IPs etc are a load of crap and that it doesnt matter at all in the slightest and that google doesnt bother with that. Apparently its all about speed, content and only high quality links etc.

I also have some black hat associates who are professionals and think Im wasting my time as the links wont count.

What do you guys think?. Ive got maybe 10 domains all up including autoblogs and youtube video blogs linking to my money site and its inner pages. I get traffic from these sites and they rank well.

Thanks.

You may find this article interesting:

http://www.jonathanleger.com/link-ip-diversity-how-important-is-it/

My opinion is that as long as it adds to user experience, then Google won't mind.

However, even if it doesn't add to user experience I think it would still be ok if each site was built for itself...meaning that the site wasn't built just for the purpose of helping another site rank.

You can see an example at thewirecutter[dot]com. Its obvious that all the blogs listed at the top of each page are owned by the same person/organization and are there just to pass authority between the blogs. But Google doesn't seem to mind...yet.

Mine are more in this structure:

The money site

- Top ranking video tutorial autoblog in the same niche, 5-10 EMD Top ranking domains advertising products and linking to the money sites product page, Top Ranking Questions site

Basically the traffic sites are their own sites and have main links on the index to my money site.

I also have some exact match domains im exploiting with spinning the content for multiple pages to net more searches on each domain (about 500 pages per domain with the same content but spun) theyre ranking quite nicely actually.

Thats about it. Theyre unique sites but same who.is, same ip and same host.