That is a really good price on the zs platinum. I had an Audigy zs with my old nf7s, and I preffered the nf2 soundstorm over the zs. I think the audigy sounded great, but I didn't notice a difference over the nvidia soundstorm. I don't know of any soundcard other than the Auzentech or the
Turtle Beach Montego DDL (and the onboard nvidia soundstorm with Nforce2) that will utilize dolby digital live. DDL turns all of your games into surround sound, otherwise, if you dont have a dolby digital (or DTS) game, you will get 2 channel sound played over 4 speakers with no sound from the center channel (that is when playing through a digital connection).
If you can live without DDL (I cant ) then you might check out some turtle beach cards, they are very good performers for a decent price. The
Chaintech AV-710 is very cheap and uses the Envy24 chipset, it's also supposed to be a spectacular card
And a final note, nearly all soundcards made today will support 7.1, they are all backwards compatible with 5.1 (that ZS you linked to is a 7.1 card also) So it wouldn't hurt to have 7.1 capabilities if you ever decide to buy into it.