Association Football
Arsenal v T*ttenham - Tottenham
Liverpool v Everton - Liverpool, Kewell played for them, and they now have 'nando
Man Utd v Man City - Citeh.
Liverpool v Man Utd - Pool, obviously
Rangers v Celtic - Celtic, Macca played for 'em
Barcelona v Real Madrid - Real, don't particularly dislike either team, but Raul only played for one of them.
AC Milan v Internazionale - AC
England v Argentina - England
Rugby Union
The All Blacks v The Wallabies - Wallabies, obvs
The All Blacks v The Springboks - All Blacks, Springboks a bunch of dirty so 'n so's.
England v France - France, bitterness over '03 & '07 WC's etc.
Leinster v Munster - Who?
Rugby League
NSW v QLD - Maroons, queenslander and all.
Wigan v St Helens - St Helens - Gidley played for 'em, don't particularly care though.
Kiwis v Kangaroos - Kangaroos
Aussie Rules
Carlton v Collingwood - Carlton, despise everything about Collingwood. It's CEO, players & fans. Oh, and they're still bitter about how we crushed them in '02/'03 (Matt to respond

)
Cricket
England v Australia - Australia, obv
Pakistan v India - Depends on the players at the time.
Yorkshire v Lancashire - Lancs
NSW v Vic - NSW, nobody likes victoria.