I picked up an external usb hard drive enclosure and a Western Digital 320 gig 7200 rpm hard drive.

OSX has several hard drive formatting options. Do I want to use journaling or non journaling for this external hard drive?

If I eventually want raid, do I buy another external drive and mirror them?

I'm going this for more HDV storage to use with I-Movie and Final Cut HD.

As discussed elsewhere, my personal experience is that journaling creates a problem with FCP's print to video, even on a fast internal SATA drive on my dual G5. I didn't have problems capturing or editing on a journalled drive, just printing to video (which is extermely finicky). Not sure what issues this might have with iMovie since I only use FCP.

USB drives are generally frowned upon for video so I've avoided them myself. Although the transfer rate is theoretically higher than FW400, the drive will be competing with your keyboard, mouse, printer and any other USB peripherals and may not deliver the sustained transfer speed needed. Let us know how it works out for you.

Funny that you mention this, I just came back from Staples where I needed to pick up some office supplies. I thought I'd get a firewire drive to start a new project on, but they only had USB drives so I didn't buy anything.

Note that I've moved this thread to our Mac editing forum. The "direct to disk" forum is intended for discussion of hard-drive based portable video recorders.

I bought the enclosure mainly for storage and because it was about $3.00 with rebate. If it doesn't work, I'll get a firewire case. Any maybe another case for my Plextor dual layer DVD drive/burner.

Funny that you mention this, I just came back from Staples where I needed to pick up some office supplies. I thought I'd get a firewire drive to start a new project on, but they only had USB drives so I didn't buy anything.

The exact same thing happened to me the other day too. I then went to Best Buy and they didn't have any firewire enclosures either.
The sales guy tried to tell me that USB2 is better than FW400 because it is "faster." This, of course is totally untrue.
The theoretical burst rate of USB 2 is 480mbps, but because Firewire400 is isosynchronus, it can maintain constistent data transfer rates from each drive no matter how many drives are attached. USB2 on the other hand realistically only sustains around 150mbps, and that's when there is only one drive plugged in! Firewire 400 can sustain around 300Mbps.
The other problem is that you can't daisy chain USB2 drives, so a USB2 powered hub is required if you don't have enough spare ports.
I don't mind USB2 on my iPod, or for data archiving, but I would never use it for editing.

As for the journaling question: I always format with journaling and haven't had any problems with print to video (I use Dual G4 and CoreDuo machines.) Journaling basically maintains a map of where files are on a drive. In the even that you accidentally disconnect an external without trashing (unmounting) it first your should suffer no ill effects and no data loss.

If a person just reads the specs, usb2 appears faster, but most people who deal with editing probably soon realize it's not.

I have a bluetooth keyboard and mouse built in, so unless it somehow uses the usb bus at least nothing else will use the usb bus. It's more like Wi-Fi although a quick google didn't reveal any bus info.

However, I suspect USB 2 might be taking the "short" bus.

Got any case recommendations? I doubt that all cases are created equal, in this case anyways.

As discussed elsewhere, my personal experience is that journaling creates a problem with FCP's print to video, even on a fast internal SATA drive on my dual G5. [/i]
Hope you have a great UPS...