Quality card (no shoddy VIA or ALi chipsets) that works without custom drivers. This card has NEC and Ti chips.
I put this in my HP server running Snow Leopard server and it works a treat. The card has a floppy power port so that you can run portable drives off the FW800 or USB ports without needing external power supplies. Note that there are three USB and FW800 ports each, but one of each points internally, so that you can cable it across to the front of your computer for easier access.
I got mine new off fleabay for more than this when the going rate was and still is £70+ for this card. It is not for everyone, but if you have FW800 peripherals, it is just about the cheapest card, and being PCI Express does not require a 64bit PCI slot like some of the budget FW800 only cards, which most motherboards lack and leads to clocking the card down to FW400 speeds.
Product Description: Belkin FireWire 800 and USB 2.0 PCI Express Card USB / FireWire adapter - 3 ports
Device Type: USB / FireWire adapter
Form Factor: Plug-in card
Interface (Bus) Type: PCI Express x1
Ports Qty: 3 ports
Auxiliary Ports: 3 x Hi-Speed USB
Data Link Protocol: IEEE 1394b (FireWire 800)
System Requirements: Microsoft Windows 2000 / XP, Microsoft Windows Server 2003
Manufacturer Warranty: Limited lifetime warranty
Specs from Play.com, but I can vouch that this card works on Windows 7 64 bit and OSX, too. No additional drivers needed. Not tried it with Linux, but I would be surprised if it didn't work out of the box.