A.) Ask the biggest wine snob you know, in a conspiratorial tone, "If you were going to buy wine for the biggest wine snob you know, what would you buy?" Devious, but effective.
B.) Ask the finest wine merchant. Not at all devious and very effective.
Back in the late '80's, my late wife (then my fiancée) and I went to Morrell & Company in NYC with a modest budget to begin a wine collection. The wine journal we had begun had few entries, and were mostly reds. The only way we were going to round out our knowledge and experience was with expert help.
The staff was not only helpful and courteous, but took a real interest in our likes, dislikes, goals and budget. The dozen bottles we acquired were a well-rounded selection of varieties and types that helped us learn more about what to focus on in the future.
We did splurge on one sparkling wine: Charbaut & Fils Certificate Blanc de Blanc '79. Although we adored Asti, it turned out to be a revelation. If possible (and available), consider trying the '75 vintage of this beauty.
Morrellwine.com - America's Premier Wine Merchant. Consult with them about how to buy fine wine -- either for yourself or the biggest wine snob you know.