I was interested in discussion about how to open a bottle of wine, drink a bit, and then save the remaining portion to fight another day. The general idea was to pour it into a smaller bottle to reduce the amount of O2 that comes into contact with it. The obvious smaller bottle to use was a wine half-bottle.
But oddly enough, wine half-bottles really aren't ideal for this purpose. If the amount of wine remaining is less than a half-bottle, there are O2 problems again, and it's difficult to pour from a full bottle of wine into a half-bottle without a funnel of some kind.
Plastic 1/3 liter water bottles are almost perfect: they're a good size, they have a wider mouth for easier pouring, and they have a tight-fitting cap. The only problem with plastic water bottles is, well...that they're plastic. They're subject to cracking and the wine will eventually discolor the bottle.
My current experiment seems to be working well. I'm using the bottles from the Starbucks coffee drink Frappuccino that's available in grocery stores. It's a glass bottle, 281 ml, with a wide mouth, and a tight fitting cork. Buy a 4-pack (I recommend the Hazelnut), save the empty bottles, run them through the dishwasher a few times to get rid of the coffee ghosts, and they're perfect for overnight wine storage.
A useful technique involving this is to save the small bottles first rather than last. If you'd like to have a single glass of wine at midnight, open a bottle, immediately fill two small bottles, and then drink the rest. In other words, save the beginning of the bottle rather than the end. I haven't yet tried storing one of the little bottles for any substantial period of time, but for one or two days, I can't tell the difference between the original bottle of wine and the stored bottle.