For at least a century vintner's have used the sponge-like tree bark to enclose wine bottles and although it may offer a less than perfect method of enclosure, it does allow for slow micro-oxynization. Now, weather that process of slowly oxidizing a wine over a period of years is limited to the cork remains to be proven, but I have the belief that because the cork does allow minute amounts of oxygen to enter into the bottle, perhaps this is just what the wine needs to transform into that time honored "aged wine taste". Time will be the determining factor as to how screw cap wines age over the decades and if they stay fresher and more lively after extended aging.
Now, I must play devil's advocate here and say that I am almost always horribly offended when a "wine consumer" walks into the cellar and acts like the wines with screw caps are no good and laughs off the possibility of buying a wine with such a ridiculous "soda bottle cap". I admit that I sometimes won't let them leave until they are in agreeance that the Stelvin tops are the best and most sanitary method of preserving a wines beauty over time. I guess that I'm not really fighting for the screw cap but more against the arrogance of the cork-lover. Arrogance and wine-snobbery just has no place with this beverage anymore and I just can't stand the snooty traditionalist attitude towards a bottle grape juice.
So, I guess what I'm really saying is that I have no preference in how a wine is enclosed. Corks, screw caps, glass, synthetic, or whatever you like, it's just a matter of aesthetics and traditions.