Was wondering since i'm putting together a workstation based on relatively high-end parts like the i7-3930k and gtx 680, should i not skimp on the audio and just buy a dedicated sound card? i'm using an Asus p9x79 pro, and im sure the onboard audio is fine, but would it boost performance to get a dedicated sound card? if so, which would work good with video editing work? any recommendations?
If the on-board sound meets your needs, then it is best to stick with it.
See the following very recent thread for some additional details regarding some high-end options:
The link Jim gave you is indeed interesting, although the original question was slightly different. A dedicated sound card is in nearly all cases a waste of money, does not improve performance, on the contrary the additional drivers and software from the card manufacturer are an extra burden for the system and especially Creative cards often cause problems. Better use the money not spent on a dedicated audio card for an extra disk where it will help performance.