Generally speaking, you want to use HFS Extended when you install MacOS X.
Being a long time UNIX user (and a long-time Mac user as well, might I add... had a "first 100 days Macintosh"), I figured that when I did a clean install of MacOS X back this summer, I'd install it in "real UNIX" mode. Hence, I did the install with the UNIX file system. To run my MacOS 9 apps, I used a second disk drive with HFS Extended on it.
This works, but it can be annoying. In particular:
- Classic won't find infromation on UNIX partitions
- A number of the installers out there won't allow you to install on UNIX partitions because they incorrectly identify them as "Server Volumes" (my most annoying example is the beta of Retrospect.
I haven't found any advantage except the ability to have "really long" file names. This can be helpful if you are trying to bring in software from UNIX that has these.
On the other hand, my PowerBook (Ti) which I had installed X on in August, runs just great with the Extended file system.
I'd definitely suggest you stick with HFS Extended.