run both! It's really not a problem for most boards as far as I know. I run an Audigy2 and use my onboard sound at the same time...it really actually can come in handy if you do different things with sound. When you install the Audigy drivers from the CD, it will automatically default the Audigy to play everything in windows and you wont even notice that you have the other one enabled still. However, if you want to use the other one too, many sound editing/playing programs allow you to select the output device to use. You can use like your onboard sound for the TV-Tuner and the Audigy for like games, etc. I have dual monitors and run a tv on one screen and game on the other...it comes in handy for that cause then my gaming sound is coming from different speakers than my TV sound. Or, also, if you're into recording music...the other sound card will give you the option of extra inputs. very handy in my opinion!
