Association Football
Arsenal v T*ttenham - Er Arsenal, I think. As a kid I liked the Spuds because I loved Lineker, but I quite like Arsenal really, ever since they beat Man U at OT in 98. It's also why I love Overmars and Bergkamp. Also I don't like Tottenham these days they are the new Newcastle and hammered us a couple of times in Cups.
Liverpool v Everton - Heh, hate this day every year. A Liverpool win much more bearable than an Everton one and blues more likely to start trouble on derby day in my experience.
Man Utd v Man City - ABU.
Liverpool v Man Utd- ABU.
Rangers v Celtic - As a kid, I rooted for Celtic because Rangers had won a load in a row. And then Rangers played at PP and I got caught up in a sea of flying bottles outside the Clipper, I was about 13 or 14, whatever age you are that sort of thing makes you not like a team.
Barcelona v Real Madrid - Real Madrid. I don't like Barca. They are like Brazil, the media constantly telling me that everyone loves them, well I don't. Uppercut once said they are what everyone wants their team to be like, well I don't. I hate being told what I should like and that's why I hate Barca. Of course, Real are no angels, far from it, lesser of two evils really. Plus a few years back they had a few English players which warmed me to them slightly.
AC Milan v Internazionale - Er never really thought about this actually
England v Argentina - Why is this even a question, anyone who picks the Argies should get a perma, simple as.
Tranmere V Bolton - Whites
Tranmere V Wrexham - Whites
Tranmere V Jester -

Whites
Rugby Union
The All Blacks v The Wallabies
The All Blacks v The Springboks - Kinda neutral on these, not a big fan of the All Blacks but it's hard for me to ever root for Crims or Saffas.
England v France - Not a big Union man anyway, will only really watch Six Nations & WC, but this one is obvious hey...England
Rugby League
Wigan v St Helens - St Helens. Same reason why I rooted for Celtic over Rangers as a kid really, also I've been stalkishly obsessed with at least eight girls from St Helens.
Cricket
England v Australia - Rivalries are supposed to be competitive, call me back when Australia actually manage to beat us.
Pakistan v India - Pakistan, usually. Changes from time to time really.
Yorkshire v Lancashire - Lancashire
FTR, hadn't seen Brumby's 'ABU' stance when I made my post but I'm hoping it will be a recurring theme throughout the thread