drewski916--
#1 - PLS stop / cancel / return that " Monster ' company cable, etc.--that is, unfortunately,
just more of the commercial " hype " associated with this new " HDTV " education. WILL NOT HELP !
To continue --- you are experiencing what might be the attempt ( by your cable company )
to simply 'squeeze' too much content into their purchased bandwidth -- consider trying to fill one's in-ground pool with a waterline from the icemaker ????
To "test' .. evaluate whether it might be the HDTV setup or cable or your neighboorhood, etc. --
one might consider ( if possible ) simply establishing an outdoor antenna --- free Over-The-Air " HD " has the least of these " compression Issues " for right now and , so, there'll be as many as 2 dozen channels in most major cities NOW broadcasting.
www.antennaweb.org
plus your ZIP ( ignore those other questions ) tells the situation in your exact case.
IF there happends to be another TV set on that same COAX, that can be a problem ... IF as many as 3 or 4 more, then, there's NO hope !
There IS much better COAX also -- called "QUAD" and more costly, it is seldom used in local cable "free" installations. IF the local company is still using mostly copper distribution plant rather than having 'upgraded' to fiber, then, this will also be a definite NO-No, beyond your control, obviously.
It does sound as though your non-HD channels are still being broadcast in 'analog' ... Comcast, as well as most others, are currently converting to all-digital rapidly ( has Nothing to due w/ Feb '09 deadline ) in order to increase how much MORE content they can "sqeeze" in -- On Demand, Two-way Cable Cards, Pay-For-View, etc..
Your choices are few .... if originally in 4:3 format, select to view these 'standard' programs in their original format, with sidebars & letterboxing @ top/bottom. To see these by just "filling up" your new 16 X 9 will result in faded colors, picture distortion, a 'stretched' appearance in objects...
Set that cable box to permit 480i & 480p --- stop automatically 'UP-converting" all to 1080i.
Do the same within the HDTV ... there are a "zillion" settings, it seems .. NO HDTV is fit to view as it comes out of the box -- every default setting is for showing at our big box store sales displays .. too bright, too much contrast, etc...although a bit over-the-top, there are commercial DVDs which aid in this "calibration" as well, for under $30.
Your set IS capable of great TV ... it MIGHT be better to consider either of the satellite companies ... I'm NOT saying this is 100 % fix, by-the-way.... just an alternative, IF after a free service call by COMCAST they do NOT remedy your issues !!
Good Luck !