I just completed my second iterration of my What's New in Diamondback presentation. I was pleased that a whole new crowd showed up. That gave me a chance to cover all my favority bits of Diamondback (read: the bits I worked on ;-).. I went over the resurrection of the VCL floating designer, true drag-n-drop development (you can now actually drag a component from the tool palette onto the form). The IDE now again also supports multiple editor windows as before. The ASP.NET and WinForms designers remain embedded.
One of my favorite features is called SyncEdit. If you've ever used recent versions of JBuilder, you have probably seen this feature. Basically you select a block of code and and a little button appears in the gutter indicating that SyncEdit mode is available. When you press the button, the Editor changes modes by highlighting the block a little differently, parses the marked block and highlights all the common identifiers within the block. Now when you edit one of these identifiers, all the others are also changed simultaneously. You can then press tab to move between each ident.
Then there is refactoring. This works not only within the entire project (even throughout units that are not specifically part of the project), but across projects within the same project group. For instance if you rename a public type or some other symbol in a C# assembly that is referenced by a Delphi for .NET project, and that Delphi project references that particular symbol, then it will also be refactored as well!
Lots-o-debugging ehhancements are also on the way. Better stack tracing. Better breakpoint window; added a toolbar, inplace editing of the breakpoint condition and pass counts, and a checkbox to quickly enable/disable a breakpoint. You can now also simultaneously debug a Win32 application and a .NET application within the same project group. Through a bit of finagling, you can also debug both Win32 and .NET within the same process! This is great for folks who are using a Win32 application in which the CLR is hosted. Such as the Diamondback IDE itself.
I haven't even touched on all the new ASP.NET, VCL, database, DBWeb, etc.. enhancements. For more information you can check out the various “live” bloggers that were covering the sessions as they were happening. There's probably more, but Google and Technorati haven't discovered them yet.