Defintely the Acoustic Edge, The Qsound algorithms do wonders for your dvds and music. You will hear noises from the dvds that make you think something else is happening in the room you're in, doors creaking,voices, footsteps, car sounds ,etc.. Qsound expands on Dolby. Dolby was designed for theaters where everyone would hear the same thing no matter where they sit and thus the sounds are limited. Who would want to sit in the rear left when the train comes roaring through from the rear left and not be able to hear the dialogue. Also the number of sound effects is limited for this reason. It is difficult to get proper spacing of different kinds of sound..birds chirping is used as an example, with Qsound if the birds are on the left, the sound would come from the left. It applies these affects to my tv card as well. What a difference! For music, I suppose it's a personal taste. The sound is separated very cleanly and you can adjust the effects.
As far as gaming, in Alice I have used options for EAX, EAX 2.0, Dolby, Aureal and Aureal 2.0, all with different effects.