I'd be really surprised if there were no IEEE-1394 I/O as this is the standard for DV video. USB would really be for stills but they may have also implemented it for video, as well. The problem with USB is that DV video has a bitrate of about 3.6 Mb/s + bitchecks and handshakes. If that's the only thing connected to a USB2 port, it would not be a problem, but if you have a mouse, printer, scanner, external drive, modem or goodness knows what else also connected to USB ports, they all have to do time sharing. Even on the much faster IEEE-1394 ports, it is hairy to, for example, bring in a DV stream to save it on an external IEEE-1394 hard disk.
P4 Core 2 Duo 2.6 GHz/Elite NVidia NF650iSLIT-A/2 Gb dual channel FSB 1333 MHz/Gainward NVidia 7300/2 x 80 Gb, 1 x 300 Gb, 1 x 200 Gb/DVCAM DRV-1000P drive/ Pan NV-DX1&-DX100/MSP8/WS2/PI11/C3D etc.