Today the VE team released an update to Virtual Earth and have converted http://maps.live.com to the new version. Of particular interest is the support of 3D in Firefox, until now it was IE only.
On the VE side the new features of V5 announced on Monday at the VE seminar were:
FireFox 2 support for all modes including 3D (Safari support for 2D only is planned for around May)
New shapes object that will have polygons, polylines and pushpins to make things more generic. (breaking change)
All mouse and keyboard events can be captured
Birdseye continous panning and minimap as per maps.live.com