Multitasking is great and it is pretty easy to navigate between different programs on Windows. Multiple sounds, however, can be very annoying when they come from different programs. The sounds from a game can interrupt the music you are listening to or you may just want the volume of certain programs to be lower. In Windows 7 you can control the volume on a per application basis using the Volume Mixer.
To access the Volume Mixer simply click on the volume icon in the taskbar and click on the Mixer link below your sound device. This will display volume controls for your open applications which you can modify as you like.
With these settings in mind you can now use different browsers for specific activities based on your sound preferences. You could open YouTube in Chrome with higher volume settings than the pages you are browsing in Firefox. That way if a website decides to automatically play sound it does not disturb as much. You can also use this options to completely mute certain applications so that you hear no sound from them at all.