Okay, so, now that I have my picture just the way I want it, thanks to the Sony Codes thread here, a new problem has cropped up: I'll be watching a show, the screen will go black (but the audio continues notwithstanding) and then the screen shows "snow" (with the audio still perfectly fine). The only way to correct it is to turn the tv off and then on again. It's happening a few times a day. Any suggestions? Any service code settings I might have tweaked to cause this? Does this mean I can get another LCD to replace it? Any help would be appreciated.

Are you using the built-in tuner or a cable box?

Sounds like a tuner failure, and i don't think it has anything to do with the service menu. Could be bad soldering or it may need a new tuner. If you're using a cable box to switch channels and not the TV's internal tuner, talk to your provider, if you're not using a cable box, the simplest fix would be to get one. :p

My 34HS510 exhibits this behavior once every few months but only on the DVI input. I have always attributed it to a loss of HDCP sync between my cable stb and tv. Cycling power on the stb resolves it immediately.

I'm on FIOS; my other tv, an lcd in the back room, does not have this problem. A DVI problem perhaps? I'll reboot the tuner and see what that does.