Perhaps my cooking isn't quite up to the level of some others', but I cook almost exclusively with Two Buck Chuck.
In the reds, I find the Shiraz is especially useful for many things because it's quite juicy and reduces well; and the Merlot is very useful too, especially for saucing or dishes calling for a drier, burgundy style red (even though Merlot isn't a Burgundy grape).
Among the whites, the Chardonnay has very little oak -- a good thing for a cooking white, but the Sauvignon Blanc is more useful. It has practically no varietal character at all -- the archtype of "generic white wine."
I also use Charles Shaw to make wine punches, such as Sangria, Kir, and wine coolers. Their Beaujolais Nouveau is very good for this, and the Shiraz is no slouch either. You can even use the Beaujolais Nouveau for a wine spritzer. Just make sure you use plenty of ice.
We go through a case of Two Buck Chuck every couple of months, easy.
In my limited experience cooking with and drinking wines, a mere forty years or so, I find that most of the characteristics which make a good wine good (as opposed to a simple table wine) cook off quickly or are completely masked when mixed as a punch. I mean which eno-subtleties will you notice coming through the 7 Up?
IMO, Two Buck Chuck is a completely reasonable and wonderfully thrifty choice for quite a few things. Of course that's just me. Your mileage may vary, and "a votre sante!" if it does. A gezundt on your kepeleh even.
As to actually drinking Charles Shaw straight, well it's drinkable. But not exactly a first choice if you can afford even a little more. Trader Joe's (Charles Shaw's primary outlet) certainly sells much better wines in the still inexpensive $4 - $7 price range. For instance, Big House Red is a heck of a bargain, very suitable for barbecues, tippling while you cook, and filling a carafe for an informal meal.
There are a lot things to consider when pairing. Expensive wines tend to be "big" wines, and not always an appropriate pairing because many simple dishes will disappear in comparison, while dishes with their own big flavors might compete. For instance, I'd choose a big red to go with a steak, but not with smoked brisket sauced in a regular tomato-based barbecue sauce.
Inexpensive, simple table wines certainly have their place. While Shaw isn't my first choice for that purpose (table wine), I'm not going to look down on it or someone who likes it either.
De gustibus non disputandum,