Vegas 9 64 bit seems very good to me.
 

Sony seems to have gotten it right with Vegas 9 64 bit version.

It runs like a charm. It seems very stable, renders faster and video loads up on the timeline very fast!

I give it a thumbs up. I like the way it previews, and while it certainly will not covert any Canopus users, it is an improvement over the preview in the 32 bit version.