I haven't followed them too closely, but I can remember the first time I heard Sung Tongs in the music office of my school's radio station. It sounded revolutionary at that time, and it still is a great album I think. I haven't heard any of their other stuff, beyond a few cursory listens to Feels.
Animal Collective were also involved in probably the worst live show I've ever seen, though not necessarily through a fault of their own. Not long after Sung Tongs came out, I went with a few friends to Wiliamsburg to see them play. We didn't have anyone to stay with in the city, and because the prospect of spending the night in Grand Central wasn't appealling to any of us, we had to be back in time to catch the last Metro North train at 1:20 AM. We figured we would, at the least, be able to catch a good 2/3rds of Animal Collective.
During this particular tour, they were supposed to be playing with Black Dice, but BD cancelled at the last minute. That was fine by me, as I didn't really feel like sitting through another Black Dice set. Unfortunately, the opening band was far worse than Black Dice could ever aspire to be. To call them a "noise band" would be too generous, to describe them, instead, how about a "too-much-money-too-many-friends-no-ideas" band. Those motherfuckers didn't start until 9:45 and played for 45 MINUTES!!!!!!
After them was Gang Gang Dance, who were pretty good, I suppose, but I was starting to get anxious and didn't pay much attention. When Animal Collective came on, we had about 20 minutes before we had to leave, still a decent amount of time. One and a half songs into the set, Panda Bear or one of those fuckers broke a string! It took him almost 10 minutes to change it, all the while chatting with the audience through a stoned haze, saying shit like "I hope this doesn't bum anyone out." We left before he finished the task and barely made the train.