When there's wine left in the bottle, I pump out air with a Vacu-Vin and put it on the shelf for the next night. I rarely notice an appreciable change on the second night. The Jacobs Creek Shiraz 2005 is a notable exception. There is definite volatility (vinegary quality) in both the aromas and flavors of the wine--not what I'd expect from a 2005 wine that only a few months ago was showing well enough to win a double gold medal from Taster's Guild.
I have nothing against a wine being made for drinking within the year. That's what I expect from La Vieille Ferme and Grand Prieur, other wines in the $7 to $10 price range. Generally, though, these wines tend to taste a little better by the time the next vintage comes out, and in most vintages they hang in there for five years or so. The Jacobs Creek Shiraz, on the other hand, appears to me to be a wine that is manufactured to show well for a limited period of time. It's not a wine I would buy in quantity.