Florence Welch, 25, beat Adele to win best solo artist and also scored best track for Shake It Out.
She said: “I’m really incredibly grateful. It is slightly strange because I’ve never been quite sure myself about whether I’m a solo act or a band.
“I’ve always thought of it as a project that I’ve started.”
The Horrors, who performed at the event along with Florence and the Machine, also won best album.
The Vaccines played too, and they were voted best new band.
NME editor Krissi Murison said of Gallagher, who took the godlike genius accolade, that he had “written more anthems in the last two decades than anyone else”.
Comedian Russell Brand said the former Oasis guitarist was “a hero to a generation”.
The songwriter, 44, paid tribute to his fans, saying: “I’d like to start by saying to all the people up there who bothered to buy a ticket, a CD, or a T-shirt because that’s what counts – the merchandise, thank you.”
Kasabian opened the night and won best British band, with the Foo Fighters getting best international band.
The Foos also won best music film for Back and Forth.
Pulp were given the award for outstanding contribution to music and singer Jarvis Cocker dedicated the award to “all the people who came to see us last year”.
Over 10 million votes were cast for the annual awards on the magazine’s website.
Highlights will be shown on Channel 4 on Saturday.
The full list of winners:
Best British band – Kasabian
Best international band – Foo Fighters
Best solo artist – Florence + The Machine
Best new band – The Vaccines
Best live band – Arctic Monkeys
Best album – The Horrors (Skying)
Best track – Florence + The Machine (Shake It Out)
Dancefloor anthem – Katy B (Broken Record)
Best video – Hurts (Sunday)
Best TV show – Fresh Meat
Best festival – Glastonbury
Best film – Submarine
Best music film – Back and Forth (Foo Fighters)
Greatest music moment – The Stone Roses reunite
Best reissue – The Smiths (Complete Re-Issues)
Best book – Noel Fielding (The Scribblings of A Madcap Shambleton)
Hero of the year – Matt Bellamy
Villain of the year – Justin Bieber
Worst album – Justin Bieber (Under The Mistletoe)
Worst Band – One Direction
Best album artwork – Friendly Fires (Pala)
Best band blog or Twitter – @Ladygaga
Best small festival – Rockness
Most dedicated fans – Muse
Hottest male – Jared Leto (30 Seconds To Mars)
Hottest female – Hayley Williams (Paramore)
Outstanding contribution to music – Pulp
Godlike genius award – Noel Gallagher
Philip Hall radar award – Azealia Banks
