Actually I had a similar problem but the disk was electricaly defective no other machine could boot even when conected to windows XP machine.
ofcourse if you conectit to windows it will trash the RDB and you could wave bye to the disk except if disk warrior can fix it .
I work as a mac technician for about 5 years and belive me mac os classic was a nightmare for users and haven for technicians, Macos X are heaven for users and nightmare for technicians!!
anyway the OS is good behaved and that are you saing point to hardware disk failure.
X server is far from perfect but belive me is more stable that windows server and you can configure it in less that 5 minutes having open directory services DNS services 10 virtual domain with smtp,pop,imap and 100 users.
Linux is more complete because doesn't have teething problems like OS X server but you need time to learn and more time to configure this.
Anyway its always a matter of taste! I 'm using OS X to my company and OSx server(with mirror raid via hardware) and I'm using PC with windows in my home my Amiga for the most common tasks again in my home and PC with debian for router on my Access Point and Back Bone links servicing the wireless Network community here in thessaloniki.
Just find for yourself what does the job better for the time/money you have and you will have your own conclusion.
