A couple of years ago a friend and I did a blind taste of the following storage methods:
2) Vacu-vin and recorking.
3) Reduce the headspace by pouring into half bottles and recorking.
4) The nitrogen/argon gas you can buy with a recork.
4 bottles were used, and one glass was poured from each bottle to introduce some air into the bottle. It was checked 5 days later. I understand I'm just a person on a newsgroup and I understand that tastes differ, so I would of course encourage everyone to see what they find works best; however, to my tastes, only the headspace reduction method retained as much of the original character of the wine as possible. The other methods were either oxidized, slightly acetic, or extremely flat.
When I open a new bottle I split the contents between two half bottles and recork. I've never tried to keep a bottle beyond 5 days, but all but the most nuanced wines retain their character admirably with this method.