The 1974 cup final was the game in which I first fell for the reds.
I had been into football for a few years before that. My parents weren't football fans but my Scottish grandpa was, and I used to go and watch Arniston Rangers, the junior team at the end of his road, with him, when I visited with my mum and dad. I used to buy the football cards with the bubblegum in so I knew a lot of the English league players and was quite obsessed with looking at the results in the Sunday paper my dad bought. The first game I can remember watching on TV was the 1972 cup final - Leeds v Arsenal. As others in this thread had said, the cup final was the only club game on TV then and it was on for the whole day - kind of a national event - obviously if your club was playing it was massive but if not, you'd watch it anyway.
I never followed a particular team back then. My best mate at school was an Everton fan and his dad took a few of us to Goodison for his birthday against Sheffield United, but luckily I wasn't convinced. He bought us a curly wurly before the match and that was the thing I enjoyed most about it. A lucky escape! Then a few weeks later, one of my other friend's parents brought a colour TV (most other people I knew still had black and white back then) and I was invited round to his house to watch the cup final - Liverpool v Newcastle.
I don't know what it was that sucked me in that day. Shankly? Seeing the red shirts against the green of the pitch? The fans and their songs? The quality of the football we played (I remember that we absolutely destroyed them)? Kev Keegan's goals? David Coleman's commentary (1-0 - goals pay the rent and Keegan does his share!)? Who knows what it was but from that day onwards, Liverpool was my team.