Dijit:
* unified look and feel for all widgets
* ambitious a11y and i18n features in every Dijit widget
* a mature CSS-driven theme system with multiple, high-quality themes
* huge improvements in system performance
* data-bound widgets
* Declarations for lightweight widget writing
* a new page parser that allows instances of any class, not just widgets
* no magic

Core:
* reduced API surface area (easier to remember and use)
* dojo.query() always available, returns real arrays
* from-scratch high-performance DnD system
* Base (dojo.js) is 25K on the wire (gzipped)
* dojo.data APIs finalized
* new build system
* new test harness for both CLI and browser use
* dojo.behavior now marked stable and based on dojo.query
* excellent animation APIs with Color animations in Base (always available)
* all the features you’ve come to count on from Dojo (RPC, JSON-P, JSON, i18n, formatting utilities, etc.)

DojoX:
* high quality implementations of previously experimental features:
* gfx (portable 2D drawing)
* data wires
* offline
* storage
* cometd (Bayeux client)
* etc.
* dojox.gfx now includes Sliverlight support
* many more features and improvements than there’s room for here