Actually, don't just go for a mini-tower... get a full-tower. Those fast a/v drives and video cards can generate a lot of heat. You'll want plenty of room for extra fans in your case. For the hardware right now, I'd opt for...(posted 9213 days ago)A dual-processor capable motherboard. That doesn't mean you need to start with two processors. Get a processor that you're happy with, because when it comes time to add another it will need to be the same type.
You'll eventually need to invest in fast a/v drives. A common setup right now is an Adaptec 2940 U2W card with Seagate ultra 2 wide compatible (LW) Baracuda drives. If you want to start with an EIDE drive, get one of the fast Seagate Medalists. The extra speed will come in handy, and with some DV setups may even be fast enough to do double-duty as both your system and audio drive.
Be careful about systems with proprietary motherboards. I'd suggest you pick out the video capture card that you're going to go with and then look at their web site for a list of approved motherboards that it works with. If you can't make a decision now, then Intel motherboards are usually well behaved and work with most cards.
I'm really fond of the Matrox G200 Millenium graphics cards. You can start with one of (AGP or PCI), and later down the road add second card for a dual monitor configuration under Windows NT. Very spiffy, no hard tech stuff involved, and the G200 cards are relatively inexpensive ($120 or so each).
As a final note, if you were planning on this system doing double duty as your general work computer, think again. Editing systems are finicky enough without the likes of Microsoft Office and other big applications being installed and mucking up the system. If you do use it for general work, before putting in a video capture card and installing the editing software I'd give serious consideration to reformating the drives and starting fresh.
-- John