64-Bit computing:Do we need it?

The question Why we need 64-bit computing? is often asked, but rarely answered satisfactorily. That this is so evidenced by the fact that the question keeps coming up again and again in online discussions. There are good reasons for the confusion surrounding the question, 1) how does the server and workstation world will use 64-bit computing, and 2) what use would the consumer world have for 64-bit computing. Does 64-bit computing really matter for a home or a office PC user. Agreed that 64-bit computing will change the face of desktop computing, but in this case the saying "Necessity is the mother of Invention" goes false. Will a layman bother to go in for a 64-bit processor. Itanium and Opteron's specs and performance sound great on paper, but considering the real world applications does they hold true? Are there any 64-bit software that can truely unleash the power of 64-bit computing. No doubt AMD Opteron's lower cost-of-entry will attact users who want to run memory-intensive applications like ERP or database management solutions but can't afford to scrap their existing x86 infrastructure, which is predominantly based on 32-bit computing. But other hand that I think that 64-bit computing is for classes and not for masses. Untill the market is full of 64-bit applications and the user will get these processors at the now 32-bit processor prices, I don't think the End-User will even be dreaming of a 64-bit Desktop machine.