I'm gonna start with Spidey's love interest, friends and all that first
Mary Elizabeth Winstead - Mary Jane Watson
Mary Jane need to be played by someone who can act and is very also hot, Mary Elizabth Winstead fits thats for me, and don't tell me those 2 picture don't look alike.
Anton Yelchin - Harry Osborn
I'm not sure if Harry will be in the reboot but he might be in sequels. Anton Yelchin just fits the role and he's a great actor I though he was awesome in Terminator Salvation.
Hugh Laurie - J. Jonah Jameson
Like everyone else, J.K. Simmons OWNED the role of JJJ, but if a replacement is needed then I think Hugh Laurie would be awesome, House is a perfect example of why he'd be great in the role.
Let's move on to the villains shall we.
Jason Isaacs - Green Goblin/Norman Osborn
My first choice was Dennis Quaid but now that's all changed. Jason Isaacs has been a father whose evil so I think he would nail Green Goblin.
Alan Rickman - Doc Ock/Otto Octavius
I don't know if I'm the first person to think this but Alan Rickman would be awesome as Doc Ock, He's a fantastic actor and he plays great villains so he get's my vote.
David Tennant - Mysterio/Quentin Beck
David Tennant is one of my favourite actors and he's my choice for The Riddler, but if he won't play The Riddler then I think he can do Mysterio, He can blend he's performances as The Doctor and Barty Crouch Jr. then I think we have a perfect Mysterio.
Sam Worthington - Shocker/Herman Schultz
I think Sam Worthington is an up and coming great actor, he awesome Terminator Salvation and he was great in Avatar but like to see him play a villain at some point and I think Shocker is a great role for him.
Timothy Olyphant - Scorpion/Venom/Mac Gargan
I agree with many people, Timothy Olyphant would own Mac Gargan either as Scorpion or as Venom.
Ben Kingsley - Vulture/Adrian Toomes
Come on, he's a great actor and looks the part.
Vin Diesel - Rhino/Alex O'Hirn
Well....he's big, but seriously Vin Diesel, to me, would be a great Rhino, but please don't use him as a main villain a henchman yes, main villain GOD NO!
Matthew Lillard - Carnage/Cletus Kasady
Some of you might disagree, but when watching Scream I thought Lillard would be a pretty good Carnage.