I'll go by best moments of each year in the decade
2000
Sweeping the Skins, seeing Ekuban drag Jeff George on the turf, Spellman clocking one of the Skins linemen in a scuffle. That game was bittersweet as Aikman's career ended that day
2001
The victory over the 49ers that day when Quincy had 240 yards passing. I thought that was his coming out party and one year after dissing the star, TO didn't even sniff the end zone that day and was crying and frustrated when Teague slammed him on the ground in the end zone after an incomplete pass his way
2002
Ugly season, but you could say seeing Emmitt Smith break the rushing record. My favorite game was beating the Skins on Thanksgiving Day. Emmitt had pretty much his last great rushing game as a Cowboy, the defense taking over in the 2nd half and wiping that smug off Spurrier's face. All the rookies played well that day, Antonio Bryant, Derek Ross, Roy Williams scoring his first TD. Chad Hutchinson had a nice passing game. Thought we would build from that rookie class
2003
Clinching a playoff berth after 3 straight 5-11 seasons in the Campo era was very satisfying. I remember Parcells saying after one of the big wins to the media "You can't call them losers anymore"......My favorite game is probably the win in NY, Parcells 1st win as Cowboys head coach, which I think led to a good season.
2004
The come from behind win vs the Seahawks on MNF after Al Michaels and company kissed Jerry Rice's behind all night. Julius Jones having a breakout game, and I thought we found our RB heir apparent to Emmitt Smith for the next several years
2005
I would have to say sweeping the Eagles that season. The first game was a thing of beauty with a 33-10 win at home, the come from behind win at the Linc with Roy Williams picking off McNabb for a TD was just as sweet to win in front of the Eagle fans. Honorable mention goes to Ware and Julius' breakout performance in Carolina that year.
2006
Knocking off the unbeaten Colts, being one of the biggest wins in recent memory for Dallas. Going on a 4 game win streak in November and finally finding our franchise QB that season.
2007
Going 12-1 to start the year, looked like the Boys were back to dominance ala the early 90s......my favorite game that year had to be the win in the Meadowlands 31-20 to sweep the Giants with TO's 50 yd TD reception from Romo, which followed with TO and Hurd doing the soulja boy on the sidelines. The giants were riding a 6 gm win streak heading into the game, after starting 0-2. Guys like Jacobs and Strahan and Pierce and Osi were taking shots at our team that week, calling us overrated and how Romo couldnt throw in the pocket. Then Dallas kicked their *** and Crayton made the statement "they always talk about us, but we seem to always come out ahead in the scoreboard." Little did we know what would occur between these two teams later that season.
2008
The win in Washington, where Newman single handedly shutdown Santana Moss, and Romo's first game back from injury, showing how important he truly is to the offense after suffering through 3 weeks of putrid play out of Brad Johnson/Brooks Bollinger. Marion Barber chewing up the last 8 minutes of the clock in the 4th qtr singlehandedly was a beauty to watch as well!
2009
So far, I would have to say the win in philly was big, but possibly could be overtaken by the win vs the unbeaten Saints in new orleans with the Cowboys backs against the wall to make the playoffs. Hopefully it can be a springboard for great things to come this season!