Green Street Hooligans.
Green Street 2
I've seen both of these numerous times. The first one more times than the second one but I decided to watch them again on Saturday.
I understand why people crap on the second one but I like it just as much as the first.
I also found out a third one came out last year but I haven't been able to find it yet.
I'm more interested in the characters than the whole Soccer/firm scene. Also the fights were pretty damn great. I also associate all soccer fans as being super hostile because of this movie and the firms.