It depends, but let me just say I'm not a huge fan of Boot Camp. I work as an Apple repair tech (just not for Apple) and almost every single time I get some system coming in because it "won't boot" and has a defective HDD, I see that it's been partitioned for Boot Camp. Wipe out the partitions, install a fresh copy of Mac OS X, and it runs great.
Granted this could have something to do with the Windows partition having been overrun with malware and screwing up boot camp somehow, but honestly I don't see how that makes things any better. It still means boot camp is a lot more fragile than it should be. It gets even worse if you set Windows to be the default OS to boot, and then something goes wrong. That's not a fun mess to try and sort out, and I've had to do it a couple of times. It tends to block you from being able to boot from the optical drive, so you either have to yank the drive and wipe it with another system or net boot, and that's not something the average person will have an easy time doing.
Of course you're analysis is correct that if Mac OS X goes down, you can't very well use VMWare, so it's a pick your poison kind of situation.
As for the 10.7 upgrade, it shouldn't affect VMWare at all. If there are any incompatibilities, odds are it will be ironed out in an update that comes out ahead of 10.7's release because VMWare will likely be getting advance developer copies of 10.7 to test with. But if you're worried, hold off on upgrading for a couple of days, monitor VMWare forums, and see what kind of issues people have, or don't have. If all is quiet on the northern front, you can install the upgrade yourself, otherwise you can hold off until things have settled.
I have VMware Fusion 3 running Win 7 on an Intel MacBook Pro with Snow Leopard and it runs great.
Since it?s obvious if the Mac OS fails, I would be unable to run Windows also.
My questions are:
1. If Windows was installed in Boot Camp and the MackBook OS had failed, would I be able to access Windows? On boot, does Boot Camp need any files on the Mac OS after it is installed?
2. Next year when Apple comes out with the new OS and I upgrade, will it wipe the Virtual or just replace some files on Snow Leopard?