How to make usability a selling point ?

A few days ago, I asked that question on the Business of Software forum hosted by FogCreek.

(I admit my post sounded somewhat baby crying. I guess I wasn't in very mood).

The discussion that followed was really interesting. People made various very good points about software (and usability) in general. I'm too tired now to make a summary and pack everything into one (or more!) articles, so I let you read the discussion ;-)