Not sure. eHomeUpgrade has secured a top secret list that's allegedly from “a confidential source working with Apple.” I'm impressed with what I've read, but I don't know if it's enough to get Windows users to switch to a more expensive platform that only has one mouse button (which is the one thing holding me back from scoring a MacBook Pro). The possible features that titilate me:

• During the Leopard install, you are given the option to create specific partitioning to accommodate M$ Vista and Linux. Reformatting your HD is not required. Depending on your processor and RAM, all OS’s can run simultaneously & independently. A (minimum) 150 GB HD is required (250 GB is recommended), and 2 GB RAM (minimum) should you wish to run more than one OS. Dual processors are required for optimum performance, though this may change in 10.5.1 or 10.5.2.
• Hooks are built-in to support an Apple PDA, but I can say no more.
• You can have 3 ‘Finder’ windows open simultaneously, much like having 3 displays, all running different applications or OS’s. If networked, any 3 computers can be displayed. Depending on the function/application, you can even Drag & Drop between displays. Password or Admin. privileges are required. (see #2 above).
• Mail, Address Book, iCal, iSight, and iChat will become one integrated application, much like Entourage (but better). Included is a customizable Auto Responder and voice activated dialing via numbers or Address Book names. You will be able to automatically send email & initiate iSight meetings, etc. that are linked/pegged to specific calendar events. This feature is called AutoPilot (see #6 above).
• An across the board speed increase of 35 – 40%. YMMV.
• Airport (Extreme only) will notify you via the airport icon flashing in the menu bar if your signal is being hijacked or used by anyone other than you authorized.

If eHomeUpgrade gets slapped by Apple within the next couple of days, I'd guess his source was revealing something too close to the truth. Certainly, Apple has to make a good showing before (or when) Vista hits the shelves. OS X and Windows will finally be competing on equal footing – if only we could get Apple to let PC users run the OS without oddball hackery.