Hi Patrick
nice home theater system. A few recommendations for your future endeavors from a music/home theater enthusiast:
1. the Marantz DV-8400 is an excellent unit for DVD/SACD/CD playback and I would highly recommend it over the DV-6400, especially since you want a new HDTV (make sure it has DVI input, the MARANTZ 8400 has this output, not so for the 8300). Both image and sound are excellent and you can find one used on audiogon or ebay for a good price. Upgrade the powercord, change the feet or find a granite slab, connect your Jaguars and off you go, believe me you won't be dissapointed. I use King Cobras in a 5.1 arrray from DVD player to preamp and another 5 King Cobras to the amp (subwoofer has it's own amp) and the sound is very clean and open ... no regrets here. I also use Audioquests VDM-5 coax cable for movies and it beats the King Cobras flat out for speed and low end punch, in this regard this DVD player has an outstanding transport.
2. I see you already have a good sub. Get rid of the monster sub cable you are using and get Audioquest's King Cobra sub cable ... BIG DIFFERENCE, almost as big as upgrading the power cord on my subwoofer. The Cobra tightens and cleans up the bass in a way I've never heard from another sub cable (I've tried top of the line from Monster and Tara Labs, again no match for the Cobra).
3. Get rid of your CV4 speaker cable. It is THE grainiest cable I've ever heard, makes high frequencies sound unbearably grainy and harsh. You can do much better for fewer dollars ... I now use a 12 awg OFC cable for my entire system made by Phoenix Cold (Quicksilver series) which sounded just as good as my Monster Sigma Retro Gold speaker cables (retail $2500) on my speakers, and the Sigmas were waaay better than the CV4's in a head to head comparison. I previously used a Monster Sigma Retro Gold cable for my center channel as well, but most center channels don't go below 60hz anyway so the accurate bass qualities of this cable are never used, why pay so much for a cable if you don't need all it's properties?
4. Don't plug your amps into that monster power strip, it limits them considerably, you'll get much better sound results if you plug them straight into the wall. I've upgraded to a Monster HTS-5100 and although it's better than the former HTS-1000 I used before, only the amps seem to benefit, power cleaning is not as good as I hoped it would be, I still have hissing present through my cone speakers.
5. If you evere have the time, consider auditioning a pair of Martin Logan Clarity speakers for fronts in your theater sytem, they beat Paradigm/Monitor Audio/Mordaunt Short/Mission/Nuance/Cerwin Vega/JBL/Tannoy cone speakers by a wide margin in my opinion. Ever since I heard electrostatic speakers, I knew that as soon as I would be able to afford them I would get them ... a move I never came to regret. The only drawback is that they are very revealing, so if you have a bright system that's exactly how it will sound, and so you'll start looking for better components and so on ... good things come with time.
anyways, better stop here.
Good luck.