My question is, I want to be able to use my pc (desktop) as the main source of my music. I've heard that I may have to convert my audio signal from digital to analog for better performance from the speakers. If so, does anyone have any advice on which equipment to buy for this?
You can start by connecting your PC with the L/R analog outputs but that is limited in quality with most soundcards. If you want to upgrade you can buy a digital to analog converter that can be connected to your PC with USB. This bypasses the soundcard. Arcam as well as many other manufacturers make these.