Back in the days of Windows 3.1 and Windows 95 it was a must to have something separate. The onboard audio on the motherboard was junk and SoundBlaster had always been my go-to choice.
I currently (hangs head in shame) am using the onboard Realtek audio and it does a fine job, but I will be looking to do some recording and upgrading to a Z or better might make a huge difference from the onboard where I can't quite get the recording levels I want.
Time to upgrade? I'm thinking so.