This is not for any specific X-Men movie idea, these are just who I think should fill the roles (of the CURRENT comic book versions of these characters (or current up to death).
See the fan-cast after the break
Here we go:

Patrick Stewart - Professor Charles Xavier.

Jared Padalecki - Scott Summers (Cyclops)

Rachel McAdams - Jean Grey

Sean William Scott - Robert “Bobby” Drake (Iceman)

Teddy Sears - Warren Worthington III (Angel/Archangel)

Steven Bacic - Henry “Hank” McCoy (Beast)

Garrett Hedlund - Alex Summers (Havok)

Kate Cassidy - Lorna Dane (Polaris)

Christian Kane - James “Logan” Howlett (Wolverine)

Rutina Wesley - Ororo Munroe (Storm)

Joseph Gordon-Levitt - Kurt Wagner (Nightcrawler)

Mike O’Hearn - Piotr “Peter” Rasputin (Colossus)

Michelle Trachtenberg - Katherine “Kitty” Pryde (Shadowcat)

Evan Rachel Wood - Rachel Grey-Summers

Oksana Akinshina - Illyana Rasputin (Magik)

Josh Holloway - Remy LeBeau (Gambit)

Ashley Green - Rogue

Maggie Q - Betsy Braddock (Psylocke)

Justin Chatwin - Julian Keller (Hellion)

Summer Glau - Laura Kinney (X-23)

William Mosley - Josh Foley (Elixir)

Katheryn Winnick - Emma Frost

Michael Beihn - Nathan Summers (Cable)

Molly Quinn - Hope Summers

Logan Lerman - Gabriel Cohuelo (Velocidad)

Rafa Nadal - Teon Macik (Primal)

Chloe Bailey - Idie Onkonkwo (Oya)

Rachel Hurd-Wood - Laurie Tromette (Transonic)

Gackt - Kenji Uedo (Zero)

Dylan Minnette - Quentin Quire (Kid Omega)

Kate Beckinsale - Neena Thurman (Domino)

Michael Spears - James Proudstar (Warpath)

Olivia Williams- Moira MacTaggert

Kevin McKidd - Sean Cassidy (Banshee)

Jamie Chung - Jubilation Lee (Jubilee)

Matthew Lewis - Jonothan (Chamber)

Mike Vogel - Sam Guthrie (Cannonball)

Kristy Lee Cook - Paige Guthrie (Husk)

Lee Thompson Young - David Alleyne (Prodigy)

Q´orianka Kilcher - Dani Moonstar (Mirage)

Skyler Samuels - Amara Juliana Olivians Aquilla (Magma)

Ziyi Zhang - Xi’an Coy Manh (Karma)

Ian Somerhalder - Nathaniel Grey (X-Man)

Thiago Rodrgiues - Roberto “Bobby” Da Costa (Sunspot)

Christian Cooke - Doug Ramsey (Cypher)

Tim Blaney - (VOICE OF) Warlock

Mary Elizabeth Winstead - Megan Gwynn (Pixie)

Josh Hutcherson - Victor Borkowski (Anole)

Matt Hill - (VOICE OF) Santo Vaccarro (Rockslide)

Christian Serratos - Ruth Aldine (Blindfold)

Lily Cole - Cessily Kincaid (Mercury)

Josh Harnett - (VOICE OF) Graymalkin (Jonas Graymalkin)

Nikki SooHoo - Hisako Ichiki (Armor)

Taylor Momsen - (as all three) Stepford Cuckoos

Dilshad Vadsaria - Sooraya Qadir (Dust)

Khleo Thomas - Nezhno Abidemi (Gentle)

Reika Akiyama - Noriko Ashida (Surge)

Tom Kenny - (VOICE OF) Robert Herman (Glob Herman)

Shawn Pyfrom - Ben Hamill (Match)

Shareeka Epps - Roxanne Washington (Bling!)

Mini Anden - Clarice Ferguson (Blink)

Kristen Bell - (VOICE OF) Danger

Chris Sanders - (VOICE OF) Broo

Emily Browning - Hope Abott (Trance)

Megan Good - Alisa Tager (Cipher)

Dianna Agron - Alison Blaire (Dazzler)

Naomi Watts - Heather Cameron (Lifeguard)

Kirsten Storms - Tabitha Smith (Boom Boom)

Katee Sackhoff - Abigail Brand

Angela Basset - Joanna Cargill (Frenzy)

Necar Zadegan - Dr. Kavita Rao

Michael Paul Chan - Yuriko Takiguchi

Paul Adelestien - Madison Jeffries

Neal McDonough - Dr. James Bradley (Dr. Nemesis)

Adhir Kalyan - Paras Gavaskar (Indra)

Emma Rigby - Meggan Puceanu

Ivan Reitman - (VOICE OF) Doop [Ivan Reitman was the voice of Slimer in Ghostbusters]

Charlie Adler - (VOICE OF) Crosta

Ariel Gade - Ernst

Tress MacNeille - (VOICE OF) Martha Johansson (No-Girl)

Jason Behr - Namor

Danielle Panabaker - Alani Ryan (Loa)

Kevin Zeger - Jean-Paul Beaubier (Northstar)

Bradley James - Pietro Maximoff (Quicksilver)

Eva Green - Wanda Maximoff (The Scarlet Witch)

Ian McKellen - Erik Lensherr (Magneto)

Ryan Reynolds - Wade Wilson (Deadpool)

Eric Bana - Dominikos “Dominic” Ioannis Petrakis (Avalanche)

Rebecca Romijn - Raven Darkholme (Mystique) [I actually thought she was great in the films and was highly under-appreciated so she stays.]

Andy Serkis - Toad

Tony Jaa - Akihiro (Daken)

Nathan Jones - Cain Marko (Juggernaut)

Joe Manganiello - Victor Creed (Sabretooth)

Chris Cooper - William Stryker

Michael Jai White - Bishop

Jason Isaacs - Mr. Sinister

Michael Clark Duncan - Apocalypse

Tilda Swinton - Cassandra Nova
OH WOW OH WOW MOST OF THESE ARE REALLY GOOD
THIS IS THE MOST PERFECT THING
(I don’t agree with...choices but gives good ideas if we wish to change faceclaims)
Everything this lady does
Les recomiendo fervientemente que vean este post :)
(( just. yes. ))
//everything except...is perfect. Ali (Alison) Larter should be cast as Emma. //