Definitely Muse. I'm still waiting to "be wrong" about Radiohead though. I haven't enjoyed anything I've heard from them.
The Temper Trap. I thought they were some shit ass mainstream band but I ended up liking their songs after a few listens.
Bright Eyes are amazing. The first time I heard them I laughed and thought they sucked. Might be my favourite band now.
I heard Starfuckers Inc. when I was like 14 from Nine Inch Nails and thought it was the worst song ever, which it is, but I never gave Trent a chance until like 3 years ago when I started listening to him seriously.
Three Days Grace and Skillet. I never really heard of them at the time and then I gave them a chance. I actually really liked their music.
1. Eminem. At first, I couldn't understand him because of his humour in some of his songs. Now I consider him my favorite rapper other than 2Pac. 2. Radiohead. I thought they were weird until I heard Reckoner. Then I looked deeper into their songs, and now I love them. 3. Believe it or not, Linkin Park. I never knew they could change so much.
Korn. After I graduated Highschool ten years ago, none of their lyrics seemed pertinent anymore... I don't even understand how I liked them before...
Same, I remember a friend showing me Helena when Three Cheers was released and I didn't like it, but later on with The Black Parade I changed my mind and eventually loved all their work.
I was wrong about Avenged Sevenfold. I thought they acted too preppy (for a lack of a better word) when they first became popular. I also found M. Shadows voice to be too annoying. Now with Nightmare, his voice is still somewhat annoying, but the music is just damn good.
Yeah, Yeah, Yeahs! I hated them sooo much when i first heard Fever To Tell. But with a couple of repeats it really grown on me.
Breaking Benjamin. I thought their name was the dumbest thing, and because of that, I didn't give them a chance. Then I heard their first record, and ohhh man.