I buy box wine for cooking and drinking. Wait, wait...don't everyone
at once!
Obviously most box wine isn't as good as most bottled wine, but there's no inherent reason that one must be better. For marketing reasons we make a distinction but there are several boxes that are pretty good and plenty of undrinakable crap in bottles.
A few I buy:
Black Box Cab- In Robin Goldstein's book The Wine Trials Black Box trounced most of the competition ranking 14th out of 135 in the New World Reds catagory. Not much nose to it and it's a bit simple but a very drinkable Cab for the equivalent of $6.25 per bottle.
Hardey's Cab- This is a pretty drinkable Aussie Cab available here for about $12 per box (about $3 per bottle!). Not fantastic but also serviceable with food or in recipes, decent enough to unwind with after work. Surprisingly enough their box Chard is actually much better than most $10 Chards I've had. I would rather drink the Hardy's Chardonnay than the Kendall Jackson (some of the most overrated wines on the planet, IMOHO).
Pinot Evil Pinot Noir- A French boxed Pinot that's really great for cooking, and you can get several batches of Coq au Vin out of one box! About $17 for a 3 litre box.
Before the more serious oenophiles string me up I'll say I tend to favor conventionally packaged wines but I do supplement them with boxed. I have wine with most meals I cook at home and like most pro cooks, I'm a lush!
You're not going to drink a $50 bottle for dinner every night.