This is Special Combo shipping ...
First, make the Product and mark it with the Price but NO weight and mark as:
Always Free Shipping: **Special, Product/Download Combo Requires a Shipping Address **
Then, you can have on your Option Name:
Media Type
Then, make the Option Values
Option Name: Media Type
Option Value: Download only (or whatever wording)
Default Sort Order: 10
Option Name: Media Type:
Option Value: CD and Download Too!
Default Sort Order: 20
Option Name: Media Type
Option Value: Pick your Favorite! (or what ever)
Default Sort Order: 0
Now add the Attributes to the Product
Option Name: Media Type:
Option Value: CD and Download Too!
Price: 1.50 (or whatever extra charge if there is one)
Weight: 1.75 (or whatever weight should be used for snail mail order)
Add the filename and days and max downloads
Option Name: Media Type
Option Value: Download only (or whatever wording)
Price: 0.00 (The charge is in the Product)
Weight: 0.00 (Their is no weight on downloads)
Add the filename and days and max downloads
Option Name: Media Type
Option Value: Pick your Favorite! (or what ever)
Display Only: YES
Default: YES
(this is so that the customer makes a "proper" choice and not just clicks add to cart without looking)
Now you should be able to order the Product either way ...