Just to pitch in. I rather dislike:
Mumford & Sons. As a listener, nothing bothers me quite like insincerity. Mumford & Sons - the band that grew up in middle-class detached houses and went to Eton because their parents could afford it insist on making pop music with boring and uninspiring lyrics about heart and hardship - something they've probably never experienced. Not to mention that they only seem 'different', 'alternative' and 'unique' to people that think banjos are exotic instruments.
Alternatives: Fleet Foxes, Simon & Garfunkel, Laura Marling
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The Vaccines. Another band that were seen as the "saviours of rock & roll" because they wrote a song that doesn't reach two minutes. I find them incredibly uninteresting and boring and would honestly much rather to be listening to bands that have tried this sort of sound before and actually got it right. There's nothing I find exciting about another British band trying to be American.
Alternatives: The Drums, The Strokes, Arctic Monkeys (between 2004 and 2007).
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The Killers. I do rather like their first album Hot Fuss, but since then I feel like they've become another band on the conveyor belt of stadium-filling rock bands that write wishy-washy stadium rock with loads of boring reverb and shit metaphors about clouds and tears, or something, that leave them sounding like an over-produced pop act that lost direction.
Alternatives: U2 (before the 90s), Coldplay (before X & Y), Elbow.
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Oasis. I really enjoy their first album, I sort of enjoy their second album, but I can't get on with their third at all. They wrote a sound in the 90s and thought it would still sound interesting towards the back end of the 00s. A one-dimensional band that Noel did well to get out of before Liam threw it into the ground.
Alternatives: Radiohead, Pulp, Blur - all around at the same time and all much better.
Some special mentions:
Bon Jovi
Kings of Leon (after Because of the Times)
Muse (after Black Holes and Revelations)
Green Day
All Time Low
You Me at Six
Nickelback
The Enemy
The Ting Tings