Oh, wow. Ok:
CA Cabs had lots of good vintages in the ‘90s. ‘91, ‘92, ‘94, ‘99. 1991 and 1994 were the most “Napa” of those vintages and often considered the best. ‘99 was a cooler vintage that produced dark wines of tremendous precision and minerality. ‘92 may have been the best of both worlds and, ultimately, my favorite. (‘95 and ‘96 were also great. Many ‘97s were outstanding fun when released, but never had the subtlety or depth of the greatest vintages. Also, most sucked at aging.)
Sonoma. 1999. Admittedly, I don’t have tooo much experience with Sonoma pre-‘99, but I’ve got enough. The cool, dry vintage was perfect for the region. (Although Chardonnay had several other great years in the ‘90’s — this is more for Pinot. And admittedly, in the early 2000s, I drank Zinfandel.)
Tuscany. Somehow Tuscany mirrors Napa. I don’t have enough pre-‘95 experience there to say for sure, but I like ‘99 the best for the long haul and for the complexity. But ‘97 was a lot of fun. ‘95s aged pretty well. But, overall, 1999.
Piedmont. Again, not enough experience to say for sure, but ‘99 for longer-term cellaring. ‘96, like ‘99, seemed more classic. ‘97 was more boysterious, but not as serious. ‘98 was somewhere in-between. All that said, based upon only a few examples, I’d say my number one would be 1990.
Veneto. 1993, 1995, 1997 were all outstanding. *probably* slightest of edges to 1995 over 1997, but it is super close. 1998 also had some great bottlings, and while I don’t have enough experience to say for sure, by reputation 1990 deserves to be mentioned.
Germany. 1998. Hands down.
Red Burgundy. I know it is 1990, by reputation. But I’ve only had one or two ‘90s. 1991, 1996, 1999 by experience.
Red Bordeaux. 1990. Easy.
Southern Rhone. 1990, though I don’t have much experience with that vintage. Also, 1998.
Northern Rhone. 1990. Also excellent, 1991 and 1999. However, despite flying in the face of popular opinion, I would put 1998 near the top of the list, as well. An outstanding, *classic* vintage. (Also, 1994 isn’t the best, but it is under-valued, imo.)
Champagne. 1990. 1996 was also phenomenal, though I’m not sure the Chardonnay crop was as good as the Pinot. By contrast, 1995 was an excellent vintage for Chardonnay, but just a decent vintage for Pinot.
Other regions I don’t think I have enough experience to say for sure.