Tough this might be useful.

Autobots:
Optimus Prime (Peterbilt 379 semi-truck) - Voiced by Peter Cullen.
Bumblebee (Chevrolet Camaro 2010) - Voiced by Mark Ryan.
Ratchet (Hummer H2 Search and Rescue Sport Utility Truck) - Voiced by Robert Foxworth.
Ironhide (GMC Topkick) - Voiced by Jess Harnell.
Wheelie (RC Monster Truck) - Voiced by Tom Kenny.
Brains (Laptop) - Voiced by Reno Wilson.
Sideswipe (Corvette Centennial) - Voiced by James Remar.
Que - (Mercedes-Benz E550) - Voiced by George Coe.
Dino - (Ferrari 458 Italia) - Voiced by Francesco Quinn.
Leadfoot (Juan Pablo Montoya #42 Target car) - Wrecker - Voiced by John DiMaggio.
Topspin (Jimmie Johnson #48 Lowe's/Kobalt car) - Wrecker.
Roadbuster (Dale Earnhardt, Jr. #88 AMP Energy/National Guard car) - Wrecker - Voiced by Ron Bottitta.
Sentinel Prime (Rosenbauer Panther fire truck) - Voiced by Leonard Nimoy.

Decepticons:
Megatron (Armored Mack Fuel Truck) - Voiced by Hugo Weaving.
Starscream (F-22 Raptor) - Voiced by Charlie Adler.
Soundwave (Cybertronian satellite) - Voiced by Frank Welker.
Shockwave (Cybertronian Tank) - Voiced by Frank Welker.
Laserbeak (Mechanical Condor) - Voiced by Keith Szarabajka.
Barricade (Ford Mustang Saleen S281E Police Car) - Voiced by Frank Welker.
Igor (Hatchling) - Voiced by Greg Berg.
Scalpel (Mechanical spider).
The Driller (Mechanical Worm).
Crankcase (Chevrolet Suburban) - Dread.
Crowbar (Chevrolet Suburban) - Dread.
Hatchet (Chevrolet Suburban) - Dread.

Humans:
Sam Witwicky (Shia LaBeouf).
Carly Spencer (Rosie-Huntington-Whiteley).
Major William Lennox (Josh Duhamel).
Sargeant Robert Epps (Tyreese Gibson).
Hardcore Eddie (Lester Speight).
Ron Witwicky (Kevin Dunn).
Judy Witwicky (Julie White).
Seymour Simmons (John Turturro).
Dutch (Alan Tuddyk).
Bruce Brassos (John Malkovich).
Dylan Gould (Patrick Dempsey).
Charlotte Mearing (Frances McDormand).
Jerry Wang (Ken Jeong).

 

Megs, Starscream and soundwvae are not confirmade yet, despite their survival i ntf2 they are still unconfirmade but its very Obvious they will return

 

Duhamel's actually confirmed to return.

 

someone beat me to it but I saw an interview with Duhamel where he talks about him returning to Transformers

 

With the human cast we could say confirmed since we know the actors playing the parts are returning for the 3rd film.

Robots are bit trickier since all we have seen is the return of the alt modes. Until ILM starts work on the robot modes you can't say for sure that a robot is returning. Oh wait sorry I almost forgot Prime and Bumblebee are confirmed since ILM said that their robot modes were being updated a bit. No word yet if other robots are getting updates on their robot modes yet or who the new robots will be for the third film.

 

Stickied. If someone wants to take charge of both fact-checking and keeping the list updated I will happily keep the OP updated with any and all changes.

 

When was leo spitz confirmed?

 

Last Year and it was aslo confriamde that leo will have a More bigger role in this film

 

We've still need some more Aerilbots & Stunticons to go,and Big Bad Baddie in TF3 (I hope is Unicron.)

Edit:And it's not Unicron.

 

can we fix the names of Mudflap and Silverbolt?

 

Simmons and Sideswipe will hopefully return. I like 'em.

 

I think it's safe to say Sideswipe and Jolt are in.... Yeah alright I'm only this because of Nefarious, which is great!  

 

I think it's safe to say Sideswipe and Jolt are in.... Yeah alright I'm only saying this because of Nefarious, which is great!  

 

I do think that Screamer should lose the tats. So pointless.

 

July 1, 2011....that will be the confirmation date. Everything up to that is assumption and speculation.  

 

If anybody wants to grab some picture resources I can shove those in th OP as well  

 

The production crew said they wanted to expand on the backstories of established characters so I'd say Sideswipe and Jolt are highly probable as well as Soundwave.

Starscream I would call a given. They would just make him disappear from all existence after that ending in ROTF.

Oh and did anyone else see the Junkion concept art? We could put Wreck Gar/Junkion(s) under the maybe category

 

I hope they bring the surviving characters back with more dialog and action sequences. I felt they are VERY UNDERUSED except for Bumblebee and Prime. Anyone else agrees???

 

I say it's time we take Megan Fox/Mikaela Banes off the list.

 

they should defiantly put jolt in the movie and give him a better role unlike the last part