We recently looked at moving our environments to VMware's Stage Manager and Lab Manager products. A large majority of our production, authoring/staging, integration and development environments are already virtualised on ESX so these new products an attractive option--they build on top of the ESX offering. The server structure was architected around the assumption MOSS 2007 content deployment works as expected in the case of westernaustralia.com but since it doesn't an admin does a daily stsadm backup/restore from authoring to production--horrific.
Stage Manager sounds great in theory. Each environment is sandboxed and it takes the thinking out of dev vs prod because dev used to prod and prod is now dev and vice versa. Each environment is packaged up to include everything it needs (AD, database, web, etc). In practice, making this work with MOSS and our existing stage/prod-based content setup (not to mention public networking, host headers, security, machine names... in MOSS, and whatnot) wasn't quite there. If you are successfully using SM with MOSS I'd love to hear from you.
Lab Manager is a complimentary product for efficiently provisioning development (er, lab) environments. Your base image is stored as a template and it gets provisioned on request. This way I don't have to build a new VM for every new dev starting with us and individual developers don't have to spend too much time keeping their development environments up-to-date. We've previously run MS VPC 2007 and while it does the trick, Lab Manager really promises to simplify this stuff. We haven't finalised our purchase yet but I'll let you know how we get on with the product.