I have been to Paris, Rome (where I saw a Liverpool fan being stabbed up his backside) then had time out then later on Istanbul / Athens. Athens was scary but this time Liverpool fans drunk as skunks and ugly mood. Istabul stuck out there 24 hours, Athens about 16 hours. The only one I really enjoyed was Istanbul / Paris the rest was awaful looking back. To be honest something like the Carling Cup is probably the way to go I went against Utd in 2003 at Millenium it was great.
I was there in Cardiff for the Carling Cup final against United and I had a different experience. I saw United fans starting fights everywhere. They were hanging around corners in groups looking threatening, and every now and again a fight would break out, but credit to the police, they were on the scene in numbers within a minute or so!
After the game I was walking down a street outside the ground with my Dad & uncle. I had a Liverpool jersey and tracksuit top on and this United fan around 50 years old was walking past me and said "good idea going down there with that on d*ckhead". Then I see tons of United supporters clogging up the street ahead, and had to take my Dad's jacket to cover up. Just before that, another United fan had walked past me and intentionally shouldered me hard. I just sniggered and walked on.