Ed,
Personally I wouldn't make this one way or the other. I would make it either a snap in, or a merge code that you can put wherever you want. Everyone has a different look and feel to their website, having the option to place it wherever you want it is optimum. Snap ins and merge codes are really cool features that allow a lot of flexibility. These are two features of Americommerce that I really like.
I would like to see the option to name a description tab what you want it to be. For example, on some of my products these tabs:
Descriptions
More Information
Details
don't tell the whole story. I would prefer to take the "more information" tab, name it "product instructions" or "how to use" giving the customer exactly what is under that tab. Being able to name the tab allows for better customization and communication based on the nature of the products each of us sell. Not all products are the same, some require different types of information in the description to satisfy the customer's curiousity, and or informational need. Getting the proper information leads to purchases. I sell fishing gear, so "instructions", "rigging instructions", are tab names that are more applicable to my particulary products, than "More Information" or "Details". Having the option to name the tab is the way to go, if it's possible.
One of the nicest features on some websites that sell electronics, is the "What's in the Box" tab, this tells the customer what comes with the product, and in that location is where I would personally put in a merge code for "Customers who bought this, bought these" The last thing you want is to upsell stuff that is already in the box, or comes with the product. This is where merge codes really shine. If I sold electronics, this is the way I would structure my product pages. This is not related to what I personally sell, but as a customer, when I buy electronics, such as cameras, etc. I like being able to know what comes with it, so I know what accessories to buy. Websites that have these features get my business, not just price.
I think that once "CUSTOMER REVIEWS" are added (HINT!), these should also be either a snap in or merge code that can be placed where you want it to be.
Best Regards,
Louis
TackleToyStore.com