Alright this should be fun.
First off let's talk speed. No other OS has previously (As of build 5342) had this sort of speed on this hardware. 768MB of ram runs almost 5x faster (seriously) on Vista. Of course this is only done by sending graphics to the DX pipeline.
Now I would go and talk about how no one else currently does a fully 3D UI like Vista but you seem to want to rule it out so let's move on.
Speech RecognitionSpeech Recognition
Speech Recognition in Windows Vista empowers you to interact with your computer by voice. It allows you to significantly limit your use of mouse and keyboard while maintaining or increasing productivity. You can dictate documents and e-mail messages in mainstream applications, fill out forms on the web using voice commands, and seamlessly manage Windows Vista and applications by saying what you see.
Seriously, what other OS does this currently? I doubt any and if they do they probably can't do it on such a wide range of drivers.
Sync CenterSync Center
The new Windows Vista Sync Center gives you one place where you can manage data synchronization in several scenarios: between multiple PCs, between network servers and PCs, and with the devices you connect to your PC.
Windows DefenderThis hands down is just a great program, I've run it and it's helped me out of binds multiple times. It's free by MS and easy to use it also has an option to restore whatever damage was done to IE.
Additionally Vista will work well with any AV/FW since it allows sort of the same protocol they did with Browsers where you chose default one and it has a standard set of system specific features for this.
Windows SideShow
Seriously this technology is amazing, it's mostly aimed torwards laptop users but here is a short description on it:
Windows Vista SideShow technology enables laptop manufacturers to include a secondary or auxiliary display in future laptop designs. This display can be used to easily view the critical information you need, whether the laptop is on, off, or in sleep mode. The convenience provided by these auxiliary displays will save time and battery life by allowing you to quickly view meeting schedules, phone numbers, addresses, and recent e-mail messages without having to start up your laptop.
PlayForSurePortable music devices that display the PlaysForSure logo will seamlessly connect to your Windows Vista-based PC as soon as you plug them in. There's no need to load any third-party software or drivers.
In other words, you can share your music more easily between portable devices and their management is a snap.
Windows Presentation FoundationAside from all this, the strongest factor in Vista is hands down WPF/XAML.
This completely changes how UI design is done and how easy it is to do it. XAML is a markup language to build Interfaces in Vista
which gives the designer more say in how an Application should look withought needing programming as a prior knowledge.
It seperates core coding and display coding which can never be a bad thing.
WPF is simply amazing, it allows you to seamlessly integrate 3D goodness into an application in an easy to use (Really, it's damn easy) API.
The sky's the limit with this stuff. If you havn't noticed, Microsoft has been more open with their development and seen in some Dev blogs are XAML and WPF demos which showcase this information. If you're still interested you can look there
XPS -- Printing Made SexyWindows Vistaâ„¢ introduces the XML Paper Specification (formerly code-named "Metro"), or XPS, that describes the set of conventions for using XML and other widely available technologies to describe a container for application data. The Windows XPS Document technologies enable end users to create, annotate, and view fixed-layout paginated documents, as well as to digitally sign and apply rights management to those documents.
This is another thing I liked, the ability to give life to your images when printing them. This thing brings images to life (I've seen a video demo, they can be found at channel9.msdn.com) and allows a faster printing method for them as well. Really, quality and speed can't be beat.
Restart Manager and Data RecoveryWith Windows Vista, users won't have to restart their computers for most updates and application installations. Windows Vista knows which applications and services are using which files, and if a file needs to be updated, Windows Vista can coordinate saving the application's data, closing the application or stopping the service, updating the file, and automatically reopening the application or restarting the service. This capability is provided by a feature called Restart Manager.
Restart Manager works with Microsoft Update, Windows Update, Microsoft Windows Server Update Services, Microsoft Software Installer, and Microsoft Systems Management Server to detect processes that have files in use and to gracefully stop and restart services without the need to restart the entire machine. Applications that are written to take advantage of the new Restart Manager features can be restarted and restored to the same state and with the same data as before the restart.
Don't have to restart the OS for updates? Cmon, how much easier can you get.
Power ManagementAs more and more computers become mobile, users will expect to treat their computers much more like they do personal digital assistant (PDAs) and cell phones today—on battery power for longer and without having to go through lengthy startup and shutdown procedures between sessions. To meet these expectations, the hardware, operating system, and applications must each do their part to help realize extended battery life and fast, reliable system standby and resume transitions.
Powermanagement for Laptops,PDAs, and the like. I mean if you can have the looks and power of Vista and not use up all your battery life..what more can you ask for?
Windows Communication FoundationThe vast majority of applications that are developed today need to communicate with other applications. The ability to share data between a wide network of services that can communicate with other platforms and devices is what Web services are all about. Windows Communication Foundation is Microsoft's unified programming model for building Web service applications with managed code. It extends the .NET Framework to enable developers to build secure, reliable, and transacted Web services that interoperate across platforms and integrate with existing investments. Windows Communication Foundation is built from the ground-up to combine and extend the capabilities of existing Microsoft distributed systems technologies, including Enterprise Services, System.Messaging, .NET Remoting, ASMX, and WSE to deliver a unified development experience.
In a nutshell, it makes it easier to build Networking applications which communicate with each other. This again adds to the already heftly list of good features Vista comes with.
-- I hope that's all you need, I can find more if you'd like. It's really quite fun.