Either would work. The speed differences between the two are trivial -- USB 2 boasts a slightly faster transfer rate, but if the FireWire advocates are to be believed, 1394 has a bus optimized for video/audio type streaming. So, 6-of-1.

I have two DVD-R burners, both IDE. One is inside my PC. I took the other, went to Circuit City and bought an ADS Pyro external enclosure that has BOTH 1394 and USB 2 connectors. I slid the IDE burner into the enclosure, popped the lid on (all of two minutes, seriously), then loaded the driver on my laptop, plugged it in, and it worked first shot. I was amazed. (The Laptop has both USB and 1394 connectors and Windows XP). The enclosure was on sale for $79, normally $99. So for the price of the burner + $100 you can make your own external drive in minutes that will work with either bus.

I've never tried daisy chaining; my laptop actually has two USB and one 1394 port, so I've had my data on an external 1394 drive and the burner on the USB port, and burned from one to the other with NERO, no problem. The DVD burner even works as a CD-ROM drive under USB 1.1, though I wouldn't bother trying to burn a DVD under USB 1.1.

USB 2.0 hubs can be had for very cheap these days, too. I've never priced 1394 hubs.

Just my two cents. Good luck!