What was somewhat a surprise for me that the keynote was too consumer oriented (or, should I say, press oriented). There was no more developer oriented talk about the underlying technologies. But that was left for the sessions I suppose

I am afraid most of the posts here, as well as the majority of the blogs around the web, make only a skin deep look on the Leopard presentation.
There is one big difference in Apple vs. Microsoft approach on the technologies provided by the OS.
Let's take Time Machine. NTFS has an edge on HFS+ because it supports snapshots on file system level. HFS+ does not. Because of this, Time Machine relies on the presence of a second/external drive. This is big disadvantage, especially for the growing number mobile users. So is it an over-hyped piece of crap? What does have Windows Vista to offer instead?
Microsoft has the underlying technology in place, but it is pretty much hidden for the user. It lacks the high-level interface and APIs to become usable by normal users and the majority of developers. It lives in the realm of system administrators (with few exceptions, like rolling back after installing a bad driver). On the other hand, Apple lacks the proper underlying low level technology yet but has a wonderful approach on using such a technology, when available (serving as an intelligent and useful backup solution in the meantime). No, it is not the fancy interface! I am talking about, think about the following:
- Time Machine is available on application level. Every application can look back for old versions of it's own files and data types. Every developer who ever used a source code management system (cvs, subversion etc.) will recognize this as a very easy to use, automatic (no installation and management) versioning system for every application which chooses to support Time Machine. It is important to note that all developers can use it in their applications.
- Even when used from the Finder, Time Machine can filter specific types of information. No, not specific extensions, but generic data types, like images and video. It can perform a search inside the deleted or modified files!
This may seem as an eye candy, or may not qualify as an advantage in a check-list like shootout, but this is what can make a difference between a feature that is never widely used (and most users even don't know it exists) and a feature you will not want to live without after getting used to it. Think about iPod-iTunes story.
I intentionally took a feature that in theory could work better in Windows. A lot of others (CoreAnimation, Image Kit, CoreImage, CoreData) do not have direct analog in Windows. What Apple does is to provide the Frameworks and APIs for everybody and create a golden standard application using them. The latest both shows the developers what they can do in their applications and raises the bar for customer expectations on applications and their interface.
With Apple market share rising more developers can consider writing Mac-only applications and further strengthen Mac OS X position.