Well, the only real game cards are those based upon Creative DSP's meaning various of the Audigy series and the X-Fi's. The latter are not selling for much of a premium right now.
Then there is the optical question and since it is not included on the card an accessory is required. The cheapest and most practical is one of any number of audio brackets commonly supplied with mainboards (perhaps you already have one?). It is simply a matter of matching up the plug to the pins on the card (some wires potentially have to be moved within the plug).
Another alternative would be switching to coaxial cable instead especially since that is included on the card's own bracket. However, adding a digital I/O bracket is really still preferable so that the card's FlexiJack can be used simultaneously for a microphone (particularly for games with VOIP).
A completely different option is to forego support for EAX 3, 4 & 5, OpenAL and hardware rendering in some games by choosing a C-Media based card such as those from Auzentech, Bluegears and perhaps other generics. The advantage if you are set on optical is the inclusion of a jack on the card's bracket and also the option of a DTS and/or DD encoder for surround effects (within the limitations of a given game's support for the card). Also the compression reduces quality slightly and has the potential to lag. However, while I have heard of the latter occuring with the old Nvidia SoundStorm I have not about the C-Media solution (but it would be something to look into as well as general research and especially into the state of the drivers).
So really, the best overall option would be an X-Fi with a bracket and perhaps using optical output for movies and music but analog for games (thus getting 6ch real-time mixing output rather than the 2ch of SPDIF). Although you may be happy with 2ch matrixing (mock surround). If cost is no barrier Creative does offer an external hardware DTS encoder which would eliminate any compromise if you are still set on either SPDIF connection.
Just to be complete, there is a software DD (AC3) encoder for the Audigy series DSP which enables 6ch SPDIF without the support drawbacks of the C-Media solutions but with the drawback of still kind of being a work in progress.
I hope that helps