>>> using FireWire, the video editing application running on the computer typically can control the camera (import, export, FF, RW, pause, stop). You don't touch the camcorder in this environment - well, maybe to turn it on and off...
>>> using this sort of (internal card or external box) there is no "digital link" from the camera - only analog. The computer does not control the camcorder. You click "import" on the computer application and press play on the camcorder.
In this analog environment, Red-Right Audio; White-Left Audio; Yellow-Video. Same as a VCR or analog signals from a satellite dish or a cable box...
I agree that a PCI card right on the motherboard *should* work best, though I have had great success with an older external FireWire-based Dazzle Hollywood (Pinnacle Systems bough them). Since you are running a Windows-based PC, you can either:
1) Get an internal PCI card-based digital-analog bridge.
2) Get an external FireWire base digital-analog bridge + a FireWire card... presuming your computer does not currently have FireWire and can handle the addition of FireWire.
3) Get a USB2 based digital-analog bridge. (not recommended)
If you go for the PCI card-based internal analog-digital card, that *could* be a "throw-away investment" if you don't keep the machine for very long. You have been telling us for a while that you want to get a Mac, so you would not re-use the internal card in the Mac - *maybe* a MacPro tower, but doubtful.
If you go for the PCI card-based FireWire card, that *could* be a "throw-away investment" if you don't keep the machine for very long. But at least the external box can be used with a Mac.
If you get the USB bridge, your PC should have USB-2. The biggest issue will be whether the video editing applications (PC or Mac) will even want to recognize the video activity on the USB port. I have not used these types of analog-digital bridges - but I have read too many issues with the compatibility and various hardware recognition issues. I can't recommend this way as a use-able option.
Your statements are confusing:
"Then I want to be able to capture the video just like the latest DV cams connected using Firewire.
I would like to know which would be better, a USB product or a PCI product"
1) Your analog camera needs an analog-digital bridge, so won't do FireWire. Though the external box might connect to the computer using FireWire, the camera connects to the box using analog.
2) But you want it to be like the latest FireWire camcorders...
3) But then you ask about USB...