I love a good argument almost as much as I love a great wine, so of course I really relish a good argument about great wine. For the past couple of years, I've had a lot of fun arguing on behalf of Spanish wines against partisans for other countries. Many of them didn't believe that Spain could challenge the likes of France and Italy, or that Tempranillo could produce wines as complex and compelling as Cabernet, Merlot, Syrah, Sangiovese or Pinot Noir.

We'll need new issues to debate, however, because these issues have now been settled decisively in favor of Spain and Tempranillo. With the arrival of the magnificent reds from northern Spain's 2001 vintage, it is no longer possible for anyone with an open mind and experienced palate to deny that Spain has joined the club at the top of the world wine pyramid, or that Tempranillo is among the world's greatest cultivars.

Since we're in need of a new question to debate, here's my candidate: If Spain is now among the world's best, which region is the best within Spain? This issue is really shaded red, since Albarino from Rias Baixas and Sherry from Jerez are clearly the best white table wines and fortifieds. However, if you ask a group of knowledgeable Spaniards which is their strongest region for reds, the fur will fly.

Priorat has its defenders, as does Toro. Rioja has even more of them, and we'll present their case here in two weeks. Today, however, it is Ribera del Duero's turn, and this region brings a good argument and a bunch of great wines to the debate.

Here's the argument, summarized from a week of interviews and tastings I conducted in Ribera del Duero in July: Priorat has great growing conditions but can't rival Ribera with wines based on Garnacha and Carinena (aka Grenache and Carignan), which can show lots of flashy, fruity power but not quite enough complexity. Toro has an advantage in making reds from a great local strain of Tempranillo, but the region's growing conditions produce wines so ripe and alcoholic that they have too much of everything except restraint.

For most of Ribera del Duero's producers and devotees, the region's real rival is Rioja. Rioja has great strengths: long tradition, widespread name recognition, commercial cooperation and big bodegas enjoying economies of scale that can make affordable wines as well as prestigious ones. And with lots of old Tempranillo vines ripening their fruit slowly in a cool northerly climate, Rioja cannot be dismissed on the ground that its wines are flashy but unsophisticated.

Ribera del Duero's most cogent defenders acknowledge all of this about Rioja but contend that Ribera makes Spain's most complete reds. The case goes that Ribera combines the complexity of Rioja with richness and depth of flavor rivaling the wines of Toro and Priorat.

How is this possible? The ripeness and depth are ascribed to the warmth and intensity of the striking daylight in Ribera del Duero's vineyards, which are high and dry at altitudes approaching 3,000 feet above sea level. Yet high-altitude temperatures plummet at night, lengthening the growing season and enhancing the freshness and complexity of Ribera's Tempranillo (which is called "Tinto Fino" locally).

Having repeatedly been both roasted and frozen in Ribera del Duero on a single day, I can vouch for the reality of these conditions. In the last analysis, however, you'll need to taste the wines to judge whether they've surpassed the Riojas coming in two weeks. The best bottles currently available here are briefly reviewed here in order of preference, with approximate prices and importers appearing in parentheses:

Vega Sicilia "Valbuena" Reserva 1998 ($140, Europvin): Yes, you'll need a special occasion to justify this, but it really is spectacular. Fully mature and very complex, yet still packed with fruit and energy, with perfect balance between fruit notes and spicy oak.

Dominio de Pingus "Flor de Pingus" 2001 ($56, Rare Wine Co.): The fact that this terrific wine is composed of the juice that didn't make the cut for this producer's top bottling (which costs about five times as much) is almost frightening. Deep and intensely flavored, but still balanced and refined.

Alion 1999 ($65, Europvin): This relatively recent project by the owners of Vega Sicilia is turning out gorgeous wines that are a little riper, fresher and fruitier than the Vega wines, which are geared more toward refinement and complexity. This superb bottling shows a great start, but stay tuned: The 2001 is a masterpiece.

Astrales 2002 ($50, Grapes of Spain): Although this is still tight and woody, the raw materials are fantastic. It you can keep your hands off of this for a couple of years, your patience will be richly rewarded.

Bodegas Mauro (Vino de la Tierra de Castilla y Leon) 2001 ($40, Europvin): This bodega is located just outside the line demarcating the Ribera del Duero D.O., so we are fudging here, but the wine is too wonderful to omit. Dark berry fruit is accented by notes of smoke, roasted meat, damp earth and spices.

Convento San Francisco Crianza 2001 ($36, Winebow): Soft, sweet and succulent, this features pure cherry fruit with just the right touch of oak.

Pago de Carraovejas Crianza 2001 ($24, Kysela): A delicious 2001 at a more-than-fair price, this shows dark, deeply flavored fruit with nice mineral edging and fine wood balance.

Vina Sastre Crianza 2001 ($27, De Maison): This has it all: Dark color, impressive concentration, deep flavors, balanced oak and fine-grained tannins for a long, soft finish.

Condado de Haza Crianza 2001 (22, Classical Wines): This is the surprise leader among current releases from the Alejandro Fernandez bodegas, with wonderfully open fruit and intriguing mineral complexities.

Condado de Haza Reserva 2000 ($34) is oakier and will take longer to develop fully, and Pesquera 2001 ($25) is very tight but amply endowed.

Valtravieso Crianza 1996 ($14, Frontier): This is a steal at a point of perfect maturity, with marvelously complex aromas on top of durably fresh fruit.

Ricardanna Tinto 2001 ($25, Grapes of Spain): This is a textbook rendition of pure, sweet, tender Tempranillo, with just a little oak and some ripe tannin helping to frame the flavors. It will ultimately be surpassed by this producer's Crianza 2001 ($36), which is woody and tight right now but sure to unwind into something special.

Arzuaga Tinto 2000 ($24, Jorge Ordonez): Delicious black fruit with nice supporting notes of cocoa and spicy oak.

Emilio Moro Tinto 2000 ($30, Jorge Ordonez): Exotic and a little funky, as usual from this producer, with wood-smoke and damp-earth and roasted-meat notes, but also fresh fruit underneath.

Fuentespina Tempranillo 2001 ($13, T.G.I.C.): Delightfully soft and open, with soft, rich, deeply flavored fruit (dark berries and black cherries) accented with interesting earthy notes.

Michael Franz will offer additional recommendations and answer questions live today at noon on www.washingtonpost.com.