Hopefully this helps explain things:
http://glennchan.info/articles/vegas/v8color/v8color.htm

"32-bit" behaves very differently than before.

Thanks for the breakdown Glenn. Great stuff as always.

It's great that Sony Vegas 8 offers 32-bit. I'm hoping the next update will address some of the bugs and work arounds.

Owning the JVC HD100 and capturing via Cineform NEO HDV, I'm wondering how much I can really benefit from using a 32-bit project in Vegas 8?

At present, my goals are to acheive the best quality videos for HD-DVD/Blu-Ray, and DVD.

Using Vegas 6 and 7, I have seen some color banding when I've pushed my footage (color corrections, levels, NR).