RGB Setting?

[ClaytonMG]

Alright, so here's my problem. I have a Sony 57" 16:9 TV with DVI input on the back. I am using the HDMI out on my Sony BDP-S1. I had it set for the HDMI-DVI thing (RGB - 25-235 or whatever) and I noticed most black levels looked more like shades of grey. So, I tried using the other setting (RGB 0-255) and the blacks look considerably more black. However, it doesn't display all levels of black unless you go into the memory setting and turn the brightness up one notch. Then it starts displaying "Blacker Than Black" blacks. So now I am wondering which setting I am actually supposed to use... And how do I use the tests on the Sony Blu-Rays to set up my brightness. I know how to do the color and everything, but I've been using AVIA for now.