I was a vegetarian for 4 years or so, mainly because my mother - who I lived with, when I was young - was too.
I saw a video about the stuff you don't see, i.e. how the animals get killed, the nazi-like extermination efficiency of it all, and it really did shock the hell out of me. I think you'd have to be made of stone not to see a video like that without being slightly wobbly afterwards.
It still bothers me a little conceptually, but I do eat meat and I've kinda come to the conclusion that I probably always will. However, I find that from a dietary point of view eating some good meat once or twice a week suits my digestive system really well, and I try to shop responsibly (although in this country that also means it costs a lot more

).
I'm a total fish freak, though.. Sushi, sashimi, pilchards, salmon, tuna, herring, mackerel, crustaceans... all staple diet items. I often 'deprive' my cat (she's spoiled beyond belief in actual fact) by noshing all the pilchards when I opened the can ostensibly for her.. Yum.