Redskins vs Cowboys without a question is the biggest rivalry, the reason why they kept Dallas in the NFC east despite their geographic location, was because of the rivalry w/ the skins, it was a rivalry even before the cowboys came to the league since washington's owner refused to give the vote for them to become a new expansion team, so owner of the cowboys bought the rights to the "hail to the redskins song" eventually both agree etc., and ever since there been amazing games, two storied franchises with 8 super bowl titles and 13 SB appearances, can't top that.
the rivalry has toned down a bit because not only because the skins, but also the cowboys have been horrible for almost the whole decade as well, cowboys slightly improved to a higher degree than the skins in the past 5 years, despite that; lets not forget that those bad skins from 05 thru 08 won 5 of 7, which included 35-7 thumpin in 05, a dramatic 14-13 win after being down 0-13 with 3 minutes left in 4th quarter in dallas, incredibly scoring 2 tds to win, sweeping the boys that year, just to mention the most recent ones for those who say that the rivalry has toned down a lot.
not to mention this year, Dallas had been scoring 30 plus points up thru week 9 against everyone they they faced, skins despite their issues and their 20 play callers on the booth, held the cowboys to ZERO POINTS all the way to the 4th QUARTER with 2:40 sec, to painfully loose it 7-6, after SUISHAM missed to key field goals. the rivalry is not completely dead, is a matter of time before in regain full force.
lets not get confused here, skins and cowboys will forever be the most legitimate rivalry in football, a true cowboy fan from dallas will tell you who their true rival is. now a different story if for those cowboy fans from PHILLY who have never been to dallas, will probably tell you its the eagles....
Get it straigt eagles your main rivals are the giants, yes our division is the best, every game without a question is a rivalry, but you have to be able to identify which one has the certificate of authenticity "skins and boys!!"
if you ask me who is best rivalry in recent memory and past decade because of the dominance, playoff app, division titles, its EAGLES vs GIANTS, with both winning the majority of the division, both went to the SB in the past decade, Giants in 2000 losing SB, Eagles in 2004 losing SB, then GIANTS 2007 winning the SB, both of those team always wanna beat each other up and hate each other and like I said all the rivalries are good but EAGLES vs GIANTS has been the best in recent memory. but the all time rivalry in our division most people will agree is in this order.
#1 rivalry.....COWBOYS VS REDSKINS
#2 rivalry.....GIANTS vs EAGLES