These I think are noteworthy:

<You can now move the selection box in the Track Motion window using the arrow keys on your keyboard>
aahh! it's back..

<The Sync Cursor button in the Track Motion window now retains its setting when the window is closed and reopened>
good too !

<The Video Preview window now updates correctly when using the arrow keys to nudge the selection box in the Event Pan/Crop dialog.

A bug has been fixed that prevented the Width and Height controls in the Event Pan/Crop dialog from handling pixel aspect ratio correctly.

A bug has been fixed that prevented the toolbars in the Event Pan/Crop window from drawing correctly in Windows XP SP2. >
<
A bug that prevented Hold keyframes from holding their settings has been fixed>
had that happen to me

<Slow and fast keyframe types are now listed correctly in the Track Motion shortcut menu (slow and fast behaviors were reversed in previous Vegas 5 releases). >
never noticed that could been a problem ,eh?

Plus I think this demonstrates that Sony is working hard on making Vegas intergrate with the new HDV technology and format.

Thanks Sony,
i'm one step closer to an FX-1, now can you do an update to fix :
A bug that prevents my wallet from holding enough money to buy an FX-1?