I am running Vista Home Premium on one computer.
When I run RegVac it typically removes a tremendous number of registry entries.
Last time I ran the program it was over one thousand entries.  
Does Vista put more entries in the registry than previous Windows operating systems?
I have noticed that many of these removed entries are labeled as shell\bags.
To me it looks like Vista is using the registry for a lot of data storage.
So far, removing these entries seems to have had no adverse effect on the operating system.
Just curious as to why the huge difference in the number of entries removed as compared with Win2k and WinXP.  

   Yes, Vista puts a lot more entries in the registry than any other version of Windows.  It is a nightmare.  What you experienced is normal for Vista.