MJK
Anthony Kiedis
Trent Reznor
Jerry Cantrell
Serg
Steven Wilson.
Eddie Vedder in association with Stone Gossard.

Cedric Bixler-Zavala - The Mars Volta

Although I'd like to post my own list up here, I've got to say that LedZepStu and Big3 have mostly summed it up for me (although I disagree with 'Metallica' and Ian Brown as being amongst the very best).

Also, I'd have to add into the mix, representing the UK:
Alex Turner of Arctic Monkeys
Alex Kapranos of Franz Ferdinand

The first because, however over-hyped it may be at the moment, he's already produced some brilliant lines ('dancing to electro-pop like a robot from 1984' still makes me smile, however many times it blares out). The second mainly because of the "I'm gonna make somebody love me and somebody is you, ooh, lucky, lucky, you're so lucky", which is just great, however much I dislike most of the accompanying music...

Drew and Kathy of CTTS and Jerry of Trophy Scars. Undefeatable.

John Parr,
Chris Rea

Bob Dylan, by miles and miles.

Roger Waters
John Lennon
Paul Mccartney
Bob Dylan
Pete Townshend
Neil Young
Kurt Cobain
Thom Yorke
Brandon Boyd
Ian Anderson
Tom Waits
Peter Gabriel
D.Boon
Bob Marley
Bruce Springsteen
John Fogerty
Frank Zappa
Bjork
Eddie Vedder
Billy Corgan

Robert Plant
Roger Waters
John Lennon
Eric Clapton
Jon Bonjovi
Rob Hofford

Bands that i don't know who in the band writes the music.. but i know one of them do..

Sunny Day Real Estate
The Appleseed Cast
Alkaline Trio

Lou Reed

Randy Blythe
Trent Reznor