I do not recall seeing a VS crash recently but here are a few things you can try:
1. You say you are working on a vista machine because you "need to use the MOSS object model". Is your VS fully patched? I think you need to install SP1 and maybe another update before VS will run well on Vista. Also, if the only thing you need from MOSS is the ability to link to the DLLs, you maybe could just copy them over to another machine and GAC them.
2. If you cannot open manifest.xsf from VS, how about closing your solution after having compiled the code and then browsing to manifest.xsf in explorer, context-clicking on it and saying "Design"? This might work.
David Airapetyan / Software Services ArchitectQdabra® Software / Streamline data gathering to turn process into knowledge