Stacy brought up a very good question a couple of days ago that can come up a lot in cooking Q&A's: What type of wine is best for cooking? Our rule around here has always been that the wine we cook with doesn't have to be the crème de la crème, but it should be of high enough quality that we wouldn't mind sipping it from a glass. Some names that come to mind of inexpensive yet fine brands are Cabot, Fetzer or Beringer. Now, these aren't necessarily the wines you'd serve the queen of England (although I've had a Beringer reserve Pinot Noir that totally knocked my socks off!), but they are fine in this regard. A Cabernet Sauvignon or a Merlot are two good, reliable options for reds. For white, I tend to prefer a Pinot Grigio or a Chardonnay.
Now - and don't laugh! - we have actually for the last year or so gotten hooked on boxed wine. Not your stereotypical White Zin Franzia (I hope I'm not stepping on any toes here - lol!), but a very tasty little Merlot that comes in a lovely black box. Each box holds the equivalent of 4 bottles of wine, and once opened, the wine will save for several weeks. (Corked wine from a typical bottle loses its zip even after just a few hours.) And the total cost comes out to be about $7/bottle. Can't beat that with a stick! It's a nice option for having a decent wine for drinking and cooking on hand without worrying about it going "bad." Boxes are actually starting to make a cool resurgence thanks to their kitschy, retro appeal (and the fact that they are superior is preserving the integrity of the product), so you should check out your local wine store to see what they carry!
Stacy, I hope this has helped answer your question.