'Grand Vin de Bordeaux': Worth the prestige and expense?

I've had a lot of people come up to me over the past few weeks at wine events saying that they can only tell if what they are drinking is wine or not when given a taste. To someone who loves wine and knows about production, geography and varietals this seems a bit ridiculous, but it is something I understand. Until a couple of years ago I too could certainly not tell whether a wine was Pinot Noir or Cabernet Sauvignon, Chardonnay or Sauvignon Blanc, or whether it was corked. Because of this paying more than the standard bottle shop/supermarket price for wine seems like an alien concept to many. Should it be? Recently I have had the pleasure of being able to try a 1990 Chateau Margaux and a 1995 Chateau Lafite-Rothschild (both between 600 and 800 pounds) and it made me think about what is worth paying for.
Obviously as a student I do not have the money to be splashing on 800 pound bottles of wine, but hypothetically would it be worth it?
The Margaux was brought in to the restaurant I work at by a group of American businessmen. The bottle was an Imperial (6 litres) and features in the display picture for this blog. It was decanted into 8 decanters on the table with about a decanter's worth of thick sediment left in the bottle. It made quite an impression and was simply a stunning addition to the evening. The group left the waiters about a full decanter for us to enjoy after the shift which worked out at about 1100-1200 pounds of wine - not a bad tip at all! It turned out to be one of the most mind-blowing wines that I have ever tried. As soon as the bottle was opened intense and deep aromatics were noticeable all around. When tried after opening, the palate is tight and concentrated following a perfect blend of smells from all over the world - notes of delicate spices mix seamlessly with truffles, ripe fruits and dark licorice. The taste is intense and lengthy, lasting for two full minutes and recurring for the next ten. Once left for a couple of hours the development is marked. The nose becomes dominated by deep dark fruits, particularly cherry. The spices and other flavours hover in the background adding complexity and depth. On the palate the wine is full and creamy, with a viscous thickness to add to the sweet tannic grip. The length of the taste is just as long 3 or 4 hours after opening as it was immediately afterwards.
This Chateau is regarded as one of the premiers chateaux in all of Bordeaux and I can see why - this year is just reaching its mature drinking age at 21/22 years old and the composure it holds suggests many more years of drinking ahead. This vintage has consistently scored between 95 and 100 points and that is certainly what I would rate it.
The Lafite-Rothschild I tasted 10 hours after it had been opened and although there was a hint of it turning from over-exposure to air, there certainly was a lot left in the tank. As one would expect from a wine so geared towards ageing this vintage was young: noticeably so. There was a tightness that left a few flavours hidden within the wine, that will open with age. Having said that, the complexity and balance is remarkable. It was not as smooth and sweet as the Margaux, and had a great deal of smokey, tobacco meatiness to it. This matched well with its truffled earthiness and dark fruit spice. The length of the wine on the palate was again extraordinary, lasting a good minute despite the length of time after it had been opened. The Chateau is situated in Pauillac in Bordeaux and is generally regarded as one of the top 5, along with Chateau Mouton-Rothschild, Chateau Margaux, Chateau Latour and Chateau Lynches-Bages. It is near impossible to fault in any way and also scores into the high 90s at tastings.
For both of these wines once they are tasted it is very difficult to find a reason why one would not buy them in a hypothetical situation. Because of the complexity of the flavours, the depth and length of the taste on the palate and history behind them there really is no way anyone could turn them down in favour any others. It seems then that 'Grand Vin' is worth the price - it still has its place.