Point #1: Don't bother with the Fraudigy Card, because the Fraudigy card is locked to a sample rate of 48 kHz -- this is the only sample rate at which you will be able to use low latency ASIO drivers with the Fraudigy. This is a pain in the ass for musicians. Believe me. Creative have tried to market this these wanky cards as musicians' cards, but they really are limiting for a number of reasons.
Don't get me wrong . . . you can make some decent quality recordings with a Fraudigy card (though you may find some of the inputs on these unusably noisy) . . . as a matter of fact, I've actually got one tune on a commercial release on which I recorded a whole band with a Fraudigy card (live stereo miking).
But, believe me, I can tell you from experience that you can do so much better for not all that much more money.
Point #2: More importantly for your situation, the optical inputs/outputs on the Fraudigy cards are SPDIF optical inputs/outputs, not ADAT. If you have an 8 channel preamp with optical output (such as the Beheringer ADA8000), you MUST have ADAT optical inputs/outputs. SPDIF is only two channels, and it's a different protocol.
I really do think that your best bet is likely to be looking for an RME card second hand off ebay or something. (RME drivers tend to be some of the best supported drivers in the business, which can be a very good thing -- I've found my older RME card to be incredibly trouble free, unlike drivers from some other companies.) You also might be able to find an EMU 1212M for around $100 if you look around. That would do you right as well (unless you are using VISTA, in which case the EMU drivers are not yet ready).
If you go for a MOTU (if you can find one cheaply), you will probably want to make sure you know what firewire chip your computer has, because there are some known compatibility issues with MOTU (as well as some other firewire interfaces) and certain firewire chips. (You can find this info on the MOTU website, or the website for any other firewire interface you may consider.) It's usually easy enough (and cheap) to get a compatible add-on firewire card if the one you have isn't compatible with a given interface, but if you are unaware of this as a potential issue, you could run up against some major frustrations when you can't get the interface to work with your computer.