Theres always the hype about big club rivalries, like BARCA-MADRID,... RANGERS-CELTIC.. Liverpool United, Arsenal spurs schalke dortmund psg marseille etc etc etc.

but sometimes we forget the even bigger rivalries on the national stage.

some very notable ones would be
Brazil-Argentina
England-Ireland
USA-Mexico
Germany-Argentina
Korea-Japan(yes both Koreas hate Japan equally its just that the South gets to play them alot more often.)
Honduras-El Salvador
Spain-Portugal.

add your input!
theres definately many more!

Ireland-England they never play last time i rember 1988 Euros

Turkey - Greece

You could say, geographically speaking, that the greatest rivalries would look something like this:

Brazil vs Argentina
Uruguay vs Paraguay
Portugal vs Spain
France vs Italy
England vs Ireland/Scotland
Germany vs Netherlands
Croatia vs Serbia
Greece vs Turkey

england france

i forgot to mention Uruguay-Argentina.

nothing like that  match, there neighbours, they have a history of killing eachother. and the matches are so intense and competitive

and the class divide in the region, the rich vs the poor.

makes it probably south America's most perfect match.

@Stanker they beat you guys at Asian cup 2007 and Olympics 2012.
and you guys only beat them by penalties in 2011.

Olympic football games are meaningless. 
We beat spain in the group stage and does it mean japan is stronger than spain? 

And what? we only beat 'em by pk in 2011? 

Now south korea can't even be matched to japan. 
All south korean suckers are like liverpool fans who live in the past. 

FIFA ranking: <http://www.fifa.com/worldranking/rankingtable/index.html>

1. Japan
2. Australia
3. south korea

Australia is rather more considerable. 

Bosnia and Serbia.

@Stanker.. Asian cup 2011.. in the semi finals, you only beat SK by Penalties.

 @stanker Im not saying South Korea is better.. im just saying there not your punching bags like you say, you guys have really been slugging out in recent years.

even though South Korea is giving you guys runs for your money, Japan is still the best team in Asia, do not doubt that for  a second right now. i have so much respect for Japan and how they have become a football power in only 20 years with the right development, spirit and passion and drive.. not just buying foreigners like Qatar to do your dirty work. Whenever Jordan play with Japan i cringe in fear because you guys are always out to crush our dreams and the memory of that 6-0 game is still vivid in my memory.

see you this tuesday stank