BNC Info Please

I have so many options for connecting my transport, jitter reduction unit and DAC that it makes me dizzy... optical, balanced, S/PDIF digital and 75ohm BNC coaxial. With my current set up, my question is what is the difference between the BNC and S/PDIF outputs? I've been using a digital IC with a BNC adapter from the BNC out to my DAC's RCA input. This seems to provide the best detail (I assume because the BNC is true 75ohm). The same IC from the S/PDIF sounds less good to me. The only BNC IC I have looks pretty generic, dare I say industrial looking gives my DAC a little less refined sound than I'm used to. What are my options? Can BNC connections be had with higher quality coaxial? Does it make any difference? Is digital cable (with adapter) from the BNC out to the RCA in the best way to go? The only input options to my DAC are RCA and BNC. Any opinions on what the best way to go is? By the way, I'm not unhappy, my Resolution Audio Quantum DAC does a fine job, but enquiring minds just gots to know. Always looking for a better mousetrap. Thanks.
use a Kimber ILLum D60 w/BNC to RCA, works better than D-60 RCA to RCA . Smoooother, use 3 D-60's the BNC to RCA is the better.
I have noticed that some of your better gear has bnc outs. Both my counterpoint transport and my wadia dac have bnc.
south43: bnc is the pro standard for digital connections. for an interesting overview of all the combos of inteconnect one might use in the digital domain, check out the review of the dcs purcell d/d "converter" in the jan, 01 stereophile. it's getting ever more difficult to parse the digital end of the audio equipment spectrum, at least for this old fart; but perhaps that's due in part to my having to wait for weeks to use the ONE computer available to expiremental psych students at the univ. of iowa back in '65 (before i was a lawyer, i was a "rat runner.") no need to say it, i don't know which is less honorable either.
Mikec, so it appears that the set up that sounds best to me currently is the best option... Thanks for the feedback.