I bought my HT (I monitor with) at the swap meet for 35 bucks
a bit of a crap shoot but it worked out well! I had nice speakers left over from my very first HT setup that I re-used.You can certainly spend whatever you want on HT receivers and speakers so knowing an approximate budget might help us recommend something.
The idea of using the creative dts-610 is so your live monitor setup (dts decoding, bass management, time delay EQ) would be exactly the same as when you playback your finished product, but the other way to go take the output of the Gigaport HD and take it straight into 6 ch amp or powered speaker setup.
River 161's example are powered full range speakers. Before I had the dts-610 I was going into my $35 dollar HT with the 6 spam inputs and that was driving my 5.1 speaker setup. Note that in 99% of HTs, if you go spam in you are bypassing ALL processing, including bass management, so if you don't have full range speakers and/or you have a subwoofer, you need to use a Bass management VST in Plogue as part of your live monitoring setup.
There's a free VST that does that, and you could add time delay, an EQ, the Gigaport HD audio device, and make it all an "HT" group.