Well to absolutely no one's surprise Amy Winehouse.
Her song Love is a Losing Game is the single greatest piece of music made since the early 90s IMO. Its lyrics, composition, and the vocals are just perfect.
Amy had the widest range of any of her contemporaries. Some of her songs are hilarious and scathing like Stronger Than Me (My god that song must make feminists heads explode!) Whilst Fuck Me Pumps is also wonderfully scathing and funny. She could also be really sexy too like Amy, Amy, Amy (which would be the perfect song for Amy Pond!) And of course she could cover lots of genres from soul to R and B to jazz to ska to even country and western. She did a cover of the Mighty Quinn on Jools Holland that's great! (Fun fact Ade Edmondson also performed on Amy's version of the Mighty Quinn. That makes old Edward Elizabeth Hitler the only man to perform on stage with Cliff Richard, The Bonzos and Amy Winehouse
What a career!)
I'm still not over Amy Winehouse's death. That's the only hard thing about listening to her music. It will be easier for future generations to listen to her, as they didn't live through her downfall like I did, and constantly hope she'd get better. Still the music holds up, and whilst I'm glad to see her recognised as one of the greats, I still think people don't give her the credit she's due for her versatility. They tend to think of her music as just being sad and tragic.
Most of the best solo singers of the past 20 years have been women IMO. Thanks to Amy in the 00s there was I think a mini British invasion just like the one in the 60s. Rather than be Boybands however it was solo female singers.
We had some great singers like Florence and the Machine (Dear god do I love Florence Welch! Big noses are so beautiful) Paloma Faith, V.V.Brown, the Noisettes, Emeli Sande, and Jessie J. Adele was the most successful after Amy of course and she was quite good, but I must admit I found her to be horribly overrated.
I also didn't like the way a lot of feminists tried to bash Lady Gaga to beef up Adele. Fortunately Gaga seems to have overcome that now (I love Lady Gaga too and Lana Del Rey. America also seemed to produce a wave of eccentric female singers from round about that time too, which Gaga herself attributed to Amy.)
In terms of old school singers I tend to like all of the classics, The Beatles, The Stones, The Doors (Love Her Madly might be my favourite.) Queen are probably my favourite old band. You can't top Freddie Mercury. I'm also a big David Bowie and Elton John fan. (I first came to appreciate Sir Elton thanks to Dan Dare, as he did a song about that, that's great. He's done a lot of good work, and had quite an interesting life. Also his guest appearance in Kingsman 2 was hilarious.)
The Sex Pistols have also always been a big fave of mine. Johnny Rotten is an arsehole, but he's strangely likable because he's an arsehole. You appreciate how unapologetic he is, even when he's doing stupid things. Also he does seem like a smart bloke under his bluster. I also respected how he spoke out against Jimmy Savile.