Jeff Loomis, Jasun Tipton, Rusty Cooley, Francesco Fareri, Ricky Graham, and Matt Bellamy.

That's just a small list of some well-known users.
"Notes are expensive, spend them wisely." - B.B. King
i do, and so does that guy, you know, that guy, from 3 Days Grace, yeah...wait no, not that one....the other one.

And i'm pretty sure the giutarist from Papa Roach uses one, but don't hold me to that
Vai uses em, Satch uses em, Tony Macalpine uses em, i think head from korn used em, pretty much the only people ive seen use em beside head are shredders. Youve heard of Vai and Satch i assume, but if you havent heard Macalpine you should check him out, incredible talent and melodies, and amazing fusion work, my favorite shredder definitely.
Chris Broderick

that korn guitarist, Head or monkey or something.
*Enter Sig Here*
Matt Heafy, Corey Beaulieu
my gear: Gibson 2008 Standard Flying V
Marshall MG100DFX
2006 Mexican Stratocaster
GAS Gear: Gibson 1959 Goldtop Les Paul
Vox AC30 Custom Classic
Jackson USA Soloist
-John Lecompt uses some (ex- evanescence)
- both guitarists from Lacuna Coil also use 7 strings.

- a lot of metal/hard rock bands can be found using 7-strings :-)
chris broderick, steve vai, some nu-metallers, some death metallers, and some jazz guys. lots use them
Quote by AA00P
Listen to the man, he's Jewish.
Ken Susi and Buz McGrath of Unearth, Behemoth use them sparingly, Stam1na, Devin Townsend, and lots of grindcore bands like The Tony Danza Tapdance Extravaganza.
Satch used one on the song "Seven String", i believe Vai used one in the song "The Audience is Listening", Petrucci uses them on a good amount of Dream Theater songs and a few of his solo album songs, stuff from Liquid Tension Experiment, and then stuff that others mentioned like Korn, Chris Broderick, Matt Bellamy*, and Jeff Loomis.

*Matt uses a 7 string ONLY on the song "Citizen Erased", in which he tuned to AADDGBe.
Jonathan Davis, Munky, and Head from Korn all use them.
7-String Legion
Quote by TheJem
Justice4AllOne pretty much mentioned all of my ideas so yeah...pointless pun post.

Quote by MightySumo
Thanks fer settin me straight on that Justice

Quote by oneblackened
I was thinking that too, Justice usually seems like a pretty knowledgeable guy.
bucky pizzarelli, and many other jazz guitarists use them
CHRIS STOREY OF ALL SHALL PERISH!! unfortunately he left the band... he is amazing tho. Was taught by Rusty Cooley.

All of the other ones I can think of were already mentioned! But, if you do get a 7, go for the LOOMIS!
LTD EC-1000
LTD DV-200
Trivium and God Forbid guitarists use 'em too
2008 Epiphone G400 Heritage CherryFUBAR
2008 Ibanez GRG 170 DX
2009 Cort KX1Q
2011 LTD H 351 NT
Randall RG 50 TC
Ernie Ball 11-54
Dean Markley
Dunlop 10's
Dream Theater, Korn, and Mushroomhead are the only bands I know of that use 7 string guitars.