Patrick, stolen lock, stock and barrel from Tom Hogarty at LR Journal Blog, here:
http://blogs.adobe.com/lightroomjournal/
"Lightroom 2 beta vs. Lightroom 2
Changes from LR2 beta to LR2 below:
Hierarchical Dates and locations in the Library Filter. (Including days of the week for the date)
The Volume Browser in the folder panel.
Improved iconography for folders, collections, collection sets and output collections.
Dedicated keyword input field in the keywording pane.
Ability to add or remove metadata filter columns.
Improved Keyword List interface. (Including filter by keyword to manage and organize keywords)
Repositioned and refined dual monitor support location and experience. (Moved from right to left and the ultimate dual monitor experience is much more polished in terms of performance and stability
Ability to set target collection for quick collection shortcut(b). (Target any collection as the target when you hit the B key)
Lightroom Web, Metadata and Export SDK available on the Adobe Dev Center
Local control improvements
Complete list of local controls including, Exposure, Brightness, Contrast, Saturation, Sharpness, Clarity and a color toning option available for the brush or gradient adjustment tool
Additional gradient adjustment tool
Improved auto-mask functionality
Improved brush performance
Additional post crop vignette options: roundness, feather
DNG Profiles Concept
DNG Profile Editor available on Labs
Profiles for our current raw support list available
Match camera JPEG looks in the Calibration tab by selection Camera Standard profile
Export to JPEG functionality in the Slideshow Module. (Intermediate format for additional authoring tools)
Enhanced output sharpening
64-bit memory handling improvementLightroom 2 beta vs. Lightroom 2 "