Next-gen Mac OS (10.6 -- "Snow Leopard"): About 10 seconds (a brief announcement that it's being discussed in an afternoon session with Bertrand Serlet).
New Mac hardware (e.g., the rumored Mac tablet): 0 seconds.
Mac hardware updates (e.g., the rumored laptop redesign/s): 0 seconds.
"One-More-Thing": 0 seconds.
I'm just waiting for this announcement from Cupertino:
Apple Inc. (formerly-and-clearly-no-longer Apple Computer Inc.) proudly announces the obliteration of any computer-related product from its catalog. Going forward, the laptop computer formerly known as the "MacBook Air" will be known as the "iPhone Maxi"*. And the segment-dominating laptop computers formerly known as the "MacBook" and "MacBook Pro" will be renamed the "iPhone Big-n-Bulky"* and "iPhone Bigger-n-Bulkier"*.
*iPhone cell phone functionality not included.