How to get rid of all shipping during checkout?

My products have shipping costs included as options that are selected during the adding of the item to the cart (because we deliver software products on different types of media, it is not possible to apply global shipping costs during checkout). Therefore, I do not want any shipping procedures during the actual checkout procedure.

So, in admin > modules > shipping, I have deactivated all shipping modules.

So, in "Step 1" of the checkout procedure, now none of the shipping options are showing (which is good).

However, clicking the "Continue Checkout" button doesn't take me anywhere. It's as if it is waiting for some shipping option to be selected.

(If I leave "Best Way" as an option, the Continue button works and moves to step 2. If I remove Best Way so that there are no options, the Continue button does nothing.)

I also tried leaving in the "FREE SHIPPING (free_shipper)" module, but it still doesn't work and advance to the next step.

Further to this: I've found ways to make products always be Free Shipping, but it seems you must at least have the FREE SHIPPING module installed, and then it shows a bunch of confusing stuff about FREE SHIPPING in the Step 1 checkout page, when I don't want to see ANY of that stuff. The customer already chose a shipping method as part as an Option Attribute. So it technically may not be FREE SHIPPING.

Example:

User purchases some software.

Option Attribute: Delivery Method:

1. Download (free)
2. Deliver on floppy disk (US) + $4.00
3. Delivered on floppy disk (International) + $8.00
4. Delivered via UPS on CD ROM + $15.00

So the user has already chosen one of these options for delivery. It could be free, or it could be something else.

So I don't want to see ANYTHING about shipping during the checkout procedure. Especially nothing telling him he is getting free shipping when he may not be. Any suggestions?

make products all virtual, shipping is skipped

Thanks, but that won't work, because they are not virtual. As I mentioned, users can choose a shipping option on a specific media (as an attribute at the time of adding to the cart), and I will then need their shipping address during check out, so it's not a virtual product.