Here is a nice reading piece from this weekend's edition of the Wall Street Journal (no subscription needed):

Are the Wines in First Class Truly First-Rate?
From Dom Pérignon on Singapore to a $19 Chardonnay on United, a tasting tour of five airlines' top offerings

The article talks about Doug Frost and how he and UA select the wines to put onboard the flights. It casts quite a complimentary tone about him, contrary to the opinions of many people on this board. I happen to agree wholeheartedly with the author: in UA C, the wines are meant to be more experimental and "fun"; you shouldn't judge them to be "bad" just because they have an obscure name, or that they cost "cheap" (most of them certainly do, and I've bought a half case of one after coming home ). In F, however, that is a different story.

The concluding point of the article (fair use):

"By the end of my tastings, ... I'd also reached a few class-specific conclusions: I'd fly Singapore for first class, United for business and I'd be happy on Air New Zealand drinking in coach...."