Besides the rewrite of the audio support using the Win7 architecture, the old sound drivers for JACK, NAS, and ESD have been removed. Aside from audio work, the graphics driver architecture has received changes for the DIB engine. Additionally, there's improved handling of the shell recycle bin, better joystick support in DirectInput, and an initial stub for VBScript support. There's also various bug-fixes, as usual.
Overall, Wine 1.3.25 looks like a rather exciting development release worth trying out this weekend. See more at WineHQ.org.