Sadly, I never was able to use the Creative Exitgy through usb thanks to them not even releasing Vista drivers. I will uninstall the realtek audio drivers for the mobo, though.
I probably am not going to swap the OP amps considering I plan on using the RCA out for the Schiit Magni, so really no need to swap them if they aren't going to help with the sound.
I am going to be using the AKG Q701s which I heard are very picky with how they like to be amplified and are 68Ohms. I also plan on buying the Schiit Modi in the future for listening to music and videos, so the Schiit Magni would be somewhat of a necessity. I'll try to dig up some reviews of people who had the Essence STX and switched to a separate amplifier and see what their findings were. I may never need a separate amplifier, but I am just keeping my options open!
EDIT: After reading a little further into the card on the ASUS Essence STX forum here, one of the OP amps is a "buffer" for the RCA outs, so I will most likely change all of them anyway. the RCA out one will be a very analytical and detailed OP amp for gaming because details and such are the most important thing and then warm "nicer" sound OP amps for the headphone out so I can easily switch between the two for what kind of sound I am looking for.
For the kind of cash you would spend on an external amplifier and good op-amps for the STX, you better off selling off the STX and getting an Audio-GD NFB-15.32 DAC/Amp, $255+shipping.