I think the top secret feature of Mac OS 10.5 Leopard will be the "Red Box" or project code named "Chameleon" -- the ability of Mac OS 10.5 to run windows applications natively without emulation. There are a couple of reasons why I think this is likely: (1) Vista has benn released -- While Mac OS 10.4 is on par or ahead of Vista, Apple needs something that would present itself as a noverwhelming proposition vis a vis Vista. Having a face lift of the Mac OS gui or finder or Time Machine is likely not going to be enough to constitute any major advancement to counter Vista -- so Apple needs to pull a stunner like this. (2) Apple has the expertise to pull this off -- think of all the experience from Classic and Rosetta. (3) This may be one of the reasons why Apple switched to Intel from PPC. (4) It makes sense -- it would encourage would-be switchers to finally pull the trigger. I think Apple would not try to implement the Windows API within Mac OS -- rather, I think Apple would simply build into Mac OS 10.5 the ability to install and run Windows OS without the need to shutdown Mac OS and reboot. So, this would likely require the users to buy and install Vista or XP within Mac OS 10.5 The reason is that this is easier, and of course, it would avoid the risk of developers being encouraged not to develop for Mac OS. If Mac OS has the ability to run windows applications without needing to install windows OS, then developers would have no incentive to develope for the Mac -- they would just develop for Windows and expect Mac users to run their apps in Mac OS. Apple already has Boot Camp -- which requires shut down of the Mac OS and reboot into Windows -- so it is clearly an advantage for Apple to come up with something that would allow users to avoid reboot into Windows. I am looking forward to this because it would send AAPL to $200 and above -- not counting the iPhone effect -- and it would also send MSFT to $10 or below.