I have a HLN507w. I have found that my set doesn't like Voom's output of 720P using a DVI cable. I set the Voom box to output in 1080i and the HLN507w works great.
Try switching Voom's resolution while your TV is on, when you reach Voom's 720P output you will see what I mean. Sometime I have to cycle the power on the HLN507w (turn the set on and off) to reset the resolution to the screen. (Note: I have not tried this with component cables only with the DVI.) The DLP resolution is "night and day" better with the DVI compared to the component cables)
I also find that the HTL507w doesn't like Voom's output of native resolution (All four red LED illuminated) when switching from channel to channel, I get a smaller screen with all sides having black bars for many of the channels. I have not played with the native resolution setting very much though.
I am interested in your findings, it seems to me that Voom's native output or 720p should be the way to go, especially for programing broadcasting in native 720p. Right now with Voom outputting in 1080i, I am sure I am losing resolution with native 720p programming.
Let me know what you discover in your research.
Terry
Samsung HLN507W
Denon AVR 3801
M&K 6.1