A reminder, suggested by this user: Don't mess with the RGB Range settings unless you know what you're doing cuz he didn't initially see much of a diff. in the menu page when he played with his RGB Range setting, so he didn't think twice about leaving it on Enhanced, but it made a BIG diff. when he watched DVDs with dark scenes.
In our dicussions, I recommended he set HDMI Format for YCbCr, instead of the default RGB, and see if his TV auto-sets for YCbCr like mine does (i.e., it's YCbCr compatible). He did that and his 52" Samsung LCD showed an immediate and "dramatic" change... it went black for at least 1-2 seconds before the picture came back up as YCbCr digital Component. (My Vizio 47" LCD doesn't do that.) This gave him his best pic for playing his commercial DVDs. He also left his Component connection to the TV cuz he gets a better pic from his cable box thru Component on his key channels.
If you want to try YCbCr for your HDMI connection, you can use the RGB Range menu to tell if your TV is compatible with YCbCr. If it IS compatible, there will be NO visible change in the RGB Range menu pic on screen when you switch between Normal and Enhanced. If NOT compatible, the 3575/76 reverts to the default RGB, and changing the setting for RGB Range between Normal and Enhanced DOES make a slight diff. in the menu pic on screen.
Per the Reminder above, there won't be a BIG change in the menu pic if your TV is NOT YCbCr compatible, so make sure you set RGB Range back to Normal before leaving the HDMI menus. That way, you won't run into darker-than-dark scenes in your movies.
CAUTION: MAKE SURE YOU'VE SELECTED THE HDMI CONNECTION ON YOUR TV before doing the RGB Range test since you CAN make changes in that menu while on OTHER connections (Composite, S-Video or Component) and, OBVIOUSLY, the RBG Range menu will have no effect on the menu pic. After making the correct settings, this user also found little, if any, diff. between HDMI and Component for normal TV watching... they were both good... but that prob. depends on your source and total system, so you'll have to experiment if you want the best PQ from every source in your system. (I get my best all-around TV/HDD watching pic with digital Composite cable cuz my analog cable feed is Composite.)
You can use QVC shopping channel for PQ comparisons of live TV since they have studio lighting, static shots, and text always on screen.
This user's TV ALSO has a setting for YCbCr but setting the TV's YCbCr ON made regular TV watching thru his cable box worse. Besides, his TV was auto-setting for YCbCr from the 3575 for his DVDs, which is what he wanted anyway.