A story a while back about ridiculously expensive speaker cables and James Randi's challenge to tell the difference between them and modestly-priced cables reminded me of a conversation I had with a wine-loving friend of mine.
He went on a wine tasting tour and sampled wines of varying quality and price. His conclusion was that he could detect the correlation between price and quality up until about $75/bottle. Beyond that point, the wines all tasted roughly equally great.
Conclusion: There's no point in my friend spending more than about $75 on a bottle of wine. Once you know the limit of your discrimination, you can use it to avoid wasting money. (One might argue that this is one advantage of having a coarse palate: You can get away with cheaper wine!)