What you get from your sound set-up will depend to a large extent on what you do with the output from your on-board sound or add-in sound card.
In other words, you should consider running the output signal through an external amplifier and some proper hi-fi speakers, rather than just using the typical computer speaker installation.
For my FSX set-up I use an add-in Creative PCI soundcard feeding two external amplifiers (one of them stereo to a pair of hi-fi speakers at the front & the other dedicated to a sub-woofer) and a pair of high-end self-amplified Apple PC speakers at the rear. The 'spacial' aspects of the sound are controlled by the Creative card, the external amplifiers and high-end speakers allowing me to provide the sound levels that I desire without any distortion - including 'feeling' the output from the sub-woofer.