This is a **late** reply, but I hope it helps:
Modern Macs use UFS (Unix File System) or HFS+ (Apple Hierarchical File System). Apple ships their new computers with HFS+ and filesystem journaling enabled. But if you install the OS from scratch by yourself, you are given a choice.
Using the DVD that shipped with the Mac, you should be able to run the hardware diagnostics to test your machine... or reinstall the OS (preserving your data)... or restore the entire drive to the original factory installed configuration (losing your data).
If it's disk corruption, you could try a program like Micromat TechTool Pro 4. It comes on a bootable CD and is often able to fix broken filesystems. I have not used TTP in ages though, so I cannot comment on any version newer than 2.0.
The best thing is to keep your data backed up... either on CD-R/DVD-R or on a USB thumb drive. That way you can always wipe the system clean and reinstall.