I have had two "wow" experiences with the D2:
The first was when I put in a power conditioner - colours improved, soundstage expanded yadda yadda yadda
The second was last night with new cables. Originally I used Ultralink HDMIPro and Audioquest HDMI-1. I like to tweak, so I then switched over to Vizionware's Hi-Wirez 1650 Series HDMI Cable.... Wow!
With regards to my Rogers cable signal (via the 8300) the picture became clearer and more 3D-like (both SD and HDTV) and I started hearing lower levels (bass) previously absent.
As for my DVD player (Pioneer DV-46AV, 480i over HDMI in to the D2), the picture also improved showing more detail and precision.
The net effect was as if I had swapped out the front end components. I got a huge kick out of this.
I could not test the Samsung 5000, I finally gave up and should be getting a Denon 3800.
For other tweakers, I hope that you find this post interesting.