Actually according to the guide / sticky
if Desert is mostly gaming (as he said he is), the Titanium is the preferred card.
If music suddenly became his preference the Xonar DX would be the better choice.
Looks like good choices, though... both could be had for less if you waited on sales, both the sound card and speaker system go on sale more often than not. Though now that you're looking to buy, Murphy's law will kick in and you'll never find a better price until after you buy.
Also, if you ship it to a Best Buy store, you can shave $10 off. They send you a little gift card or whatever. Deal Linky