By all accounts, IE10 will be a very good thing. Speed and standards both, and conquest of zombie browsers through the power of Windows Update. Fewer headaches for developers worrying about (old) IE's worldwide massive marketshare.
Recently Ted Johnson of the IE Graphics team wrote about some more good news for standards-lovers awaiting IE10's wide release.
More precisely, from Ted's announcement post:
This post expands the list of removed legacy features to include two more: Vector Markup Language (VML) and DirectX-based Filters and Transitions. Both of these features were marked deprecated in MSDN documentation as of IE9 (e.g., the first sentence of Filters and Transitions: “This topic documents a feature of Visual Filters and Transitions, which is deprecated as of Windows Internet Explorer 9”) and are now gone from IE10’s Standards and Quirks modes.
Dropping VML and DX is of course more symbolic than anything, since the world had deprecated those technologies some time ago. Accordingly, discussion in the comments clusters into roughly two groups: those that congratulate Microsoft on its commitment to emerging standards in IE10; and those that critique IE10 for not supporting WebGL (response: persistent security issues).
So no massive technological leaps here, but perhaps another encouraging sign that HTML5's strength is waxing.