The Wine code-base has been in a code freeze since January in preparation for the Wine 1.4 release, which was preceded by several weeks of release candidates. Now that the release is out the door (along with CodeWeavers CrossOver XI), the code-base has thawed and is ready for another lengthy development path to Wine 1.6.
The first set of major changes with the Wine 1.5.0 release is a new version of the Gecko rendering engine, partial support for using the Trash on Mac OS X, support for path gradients in GDIPlus, MSXML improvements, fixes to 64-bit exception handling, and various bug-fixes.
Officially, there's 80 bugs fixed in Wine 1.5.0. In terms of the Direct3D support in Wine 1.5.0, there are some changes with this release, but nothing substantive towards Direct3D 10/11.
The Wine 1.5.0 release announcement with other details and download links can be found on WineHQ.org. Coming up soon are Wine benchmarks.