Without a doubt, the 2000s were the decade of Turkey, qualifying to 3/5 big tournaments, also a very good participation in the 2003 Confederations Cup. They had their most talented generation of players this decade with stars as Rüştü Reçber, Alpay Özalan, Hasan Şaş, Tugay Kerimoğlu, Hakan Şükür, Yıldıray Baştürk, Sergen Yalçın, Emre Belözoğlu among others.
The Croatian NT was a permanent presence at big tournaments in the 2000s, only failed to qualify to Euro 2000, when their golden generation squad was still there, the new blood came to scene in the middle of the decade. Their better campaign was in the euro 2008, where they lossed by penalty shootout against Turkey. Some of the prominent players for Croatia in the 2000s were: Kovač bros., Šimić, Pletikosa, Srna, Šimunić, Olić, and Modric.
Another multipresent NT was Czech Republic. In the Euro 2000, they were drawn in the group of death, losing with top sides: France & Netherlands in tight matches, then in their best tournament Czechs reached the semifinal being eliminated by a silver goal at extra time by Greece. In the WC 2006 they were eliminated at group stage, but had the bad luck of two key players injured and another sent-off in the second game. In the 4th big tournament, they were eliminated from Euro 2008 by Turkey in a tight loss by 2-3. Could be said that Czech were an unlucky team, considering they were #2 at FIFA ranking at some moment. Among the greatest stars in the 2000s are: Nedvěd, Poborský, Jan Koller, Rosický, Jankulovski, Šmicer, Baroš and Čech
Mexico, the Concacaf powerhouse had an irregular decade. They won 2 Gold Cups, and in 2001 were very close to being the first invited NT to win Copa America beating by Colombia in a tight match. Also in the CA 2007, they had a very good tournament finishing third. In WC 2002 they won their group ahead of Italy but next were beating by USA at KO stage. In WC 2006, Mexico qualifies again to KO stage, but loses narrowly against Argentina in Extra Time. Among their main players in the 2000s: Rafa Márquez, Torrado, Borgetti, Cuauhtemoc Blanco, Guardado, Pardo and Salcido
In this decade, USA dominated the Gold Cup winning 3 times and 1 as runner-up. Their best achievement was the second place in the 2009 Confederation Cup, after defeated Spain at SF, at that time current european champion, also breaking the 35 spanish unbeaten series. USA didn't enter at Copa America but in the only edition they met, were eliminated at Group Phase. About World Cup, they qualified to both editions, knocked out quickly at WC 2006, instead of the previous WC 2002 where they reached their best finish since 1930, in the process they faced Portugal, host South Korea, Poland, Mexico and defeated by Germany 1-0. Among their main players were: Brad Friedel, Clint Dempsey, Landon Donovan, Claudio Reyna, Bryan McBride, Bocanegra, and Cherundolo.
Denmark, dubbed in the 2000s as the "Olsen Gang", even though not making great impress at final big tournaments were a constant presence. In the Euros they qualified to final events at 2 out of 3 times, reaching the quarter finals in the 2004 edition. In World Cups, at 2002 Denmark lead their group eliminating former champions France & Uruguay, but then were eliminated at KO stage. For the 2006 WCQ, Denmark was close to advance to the play-off by 1 point. In the next euro qualifiers to WC 2010, they will make it winning their group. Two out of three, again. Among their main players were: Jon Dahl Tomasson, Rommedahl, Grønkjær, Helveg, Jørgensen, Sørensen, Ebbe Sand, Gravesen and Poulsen.
Sweden, was a constant presence at major tournaments in the 2000s. In the WC 2002, Sweden surpringly topped the "group of death" ahead of England, Argentina & Nigeria, then in KO stage, they were beaten by Senegal with a Golden Goal after missing two good chances to win the match. In the next WC 2006, they were exit again in the Second Round beaten by host country, Germany. In the next chance, they were close to make it for the third time but failed at WCQ 2010 by 1 point behind Portugal. In the Euro, Sweden was present at three editions. At 2002, were exit at Group Phase after an impressive qualifying campaign. In the Euro 2004, Sweden had their best performance, losing at QF against Netherlands only at Penalty Shootout. In the next edition, at 2008 they failed to advanced from Group Stage. Among their main players were: Henrik Larsson, Ibrahimovic, Anders Svensson, Källström, Mellberg, Ljunberg, Alexandersson and Isaksson.
Well, I tried to make a brief resume of the main contenders, the top NT in the first mentions, then the group competing for the 7th to 10th spots. After this exercise, I must tempted to change my own pick for the final spot.
Which other countries could be named? From UEFA, I think Romania, Russia or Poland. From Conmebol, Ecuador, Uruguay, Paraguay or Colombia From CAF, Camerún or Nigeria looked the more consistent From AFC, the strongest were Japan and South Korea With less chances, Costa Rica from Concacaf or Australia from OFC Maybe, some of the Conmebol countries would taken a place in the original list of candidates. The consistency or the better squad is a good reason, I guess.
Well, few days are left until the Poll will close and only Portugal and Germany seems safe picks to join the top-10 NT in the 2000s alongside Brazil, Spain, France, Italy, Argentina and Netherlands.
Because others will obviously not do it, I'll give this NL summary a rep instead. Surprising record against the very top teams, this. As for what was missing: that has most probably a couple of internal and external factors. Same for a couple of other teams.