Have you had a chance to look at the Windows Presentation Foundation, yet? It is a fundamentally new concept for developing user interfaces in .NET applications. The UI definition is stored in an XML-based language called XAML which is then tied to the business logic. The user interface can be defined separate from the code which helps covering topics such as design and usability.
WPF will help design completely new user interfaces. This technology is about vectors and dynamic scaling: there is no absolute sizing anymore, no pixels, no 32x32 icons. I expect WPF to change team structures and development approaches. Just like in web development where we have web designers and web developers, the roles of programmers are likely to change. This will probably result in a new user experience.
But looking at the demands of business applications, the presentation foundation has still a long way to go. It is not easy to bind WPF forms to ADO.NET and important controls are missing.
What is your focus? If you are concerned about compatibility with earlier versions, efficiency in coding, adherence to classic design standards, you'll be looking at WinForms. WPF on the contrary provides the change to a more modern user interface and can be seen as the future technology.
How does this fit with the world that you and I are coming from? I am mostly concerned about database interactivity and about business applications.
Should you care about WPF at all? I think you should and I got inspired by a discussion that Dr. Schwichtenberg (http://mvp.support.microsoft.com/profile/Holger.Schwichtenberg) cited: WPF got compared against WinForms and VB6 against .NET in the initial release of the .NET framework. Visual Basic 6 has provided rock-solid technology back when .NET came out. There were millions of controls, code snippets, just about everything available. And .NET WinForms 1.0 was the new technology with a young history and little industry experience.
First .NET applications were rather rudimentary and less productive to develop than VB6 programs. They didn't look that good, there were no controls, no beauty, and more difficult development. But today, .NET is the state-of-the-art technology and VB6 regarded an outdated legacy platform. Would you still recommend using Visual Basic 6 or Gupta Team Developer when developing a new application nowadays? So I guess WPF can be compared to WinForms in a similar way. It is here to stay and it is up to you to find a good point for starting to work with WPF.
Switching from Windows Forms to WPF is largely a manual task and it involes a lot of preparation and training in advance. I'd rather start with this sooner than later as it will be the key technology in the years to come. Good old Windows with its WM_* messages has served us a long time but new concepts are available that provide better user interface concepts for the future. But it is not easy to get there.
Our evolutionary porting technology focuses on porting to native .NET concepts. Your SAL code is translated to C# or VB.NET and it is possible for you to adopt and change it to use WPF frontends after porting. That is the advantage of an open and transparent porting concept such as the Porting Project. Native .NET code means that we put you in a position to move on.
Unify announced some degree of support of the .NET platform in Team Developer 6.0 but following a different path. As far as I understood their plan is to A) make TD6 capable of using .NET class (as if they were COM objects) or B) include Sabertooth into TD6 to pre-convert SAL code into VB.NET and then compile it into MSIL.
I don't think you'll have a chance to actually start using WPF in your SAL applications and Team Devaloper IDE as it is a closed, interpreted and proprietary environment.
So if you want to evaluate WPF and the many other technologies available with the .NET platform, you should consider using a native porting approach with the full source code available and Visual Studio solutions, such as the porting project.