His music isn't that great, but there's been worse out there. But, all the people who actually *hate-hate* him, I have a hard time seeing why. There's far worse people out there in the World -- corrupt dictators, serial killers, idiot politicians, radical religious nutjobs, greedy businessmen who'll bankrupt a working-class family for the sake of the bottom line, irresponsible oil companies who pollute our oceans -- and you decide that a 17-year-old (albeit an arrogant one, but at that age, that's normal) is the one who needs hating-on...
Also, my respect-points for him went off-the-charts when he sang as part of Young Artists for Haiti (a Canadian charity collaboration to help out with the Haiti earthquake). If it doesn't bring a tear to your eye, then you are a hard, hard man:
http://www.youtube.com/watch?v=nB7L1BIDELc
TLDR: Even if you don't like his music (perfectly understandable), I have a hard time understanding how Justin Bieber warrants an emotional opinion as strong as "hate."