Let us start with the already established shall we...
Green Goblin = Willem Defoe
Doc Oc = Alfred Molina
Sandman = Thomas Hayden Church
Yes, in three Spiderman movies we have been given three near perfect villain portrayals. Defoe's Goblin needed a better look and Church's Sandman needed more screen time but these actors we're perfect for their respective roles and played them brilliantly.
Lizard = Dylan Baker
Of course! He has played this part in three movies now, to hand it over would just be wrong. The Lizard himself would most likely be more CGI than anything but this man deserves to be at the core.
Vulture = Pete Postlethwaite
"Not Kingsly?!" I hear you cry. No! Kingsly is a fantastic actor, maybe too good for Spiderman. No matter how good a square peg is it will never fit into a round hole. I think Pete would fit into the Spiderman universe much more convincingly.
Kraven = Gerard Butler
Do I really need to justify this? Yes there is a good argument for Josh Brolin to get into the fury waistcoat but for the same reason I chose Pete for Vulture, I think Gerard will fit into the universe better and is much more athletic.
Tombstone = Jason Statham
This might not go down too well but I think this role is great for Jason. He is built for the part and a great screen fighter. This is a villain that doesn't need a high caliber of acting talent (no offense to Statham), he is hired muscle, a killer, nothing more.
Mr Sinister = Jason Isaacs
The eyes! This guy just radiates evil. His acting is top-notch and...well, he's perfect! What more do you want?
Carnage = Robert Carlyle
Can Robert do an American accent? Would we tolerate an English Cletus Cassidy? I don't know. All I know is this guy can play psycho like Hendrix played guitar! I would love to see him have a go at this.
Galactus = Cloud
Yes, what says "devourer of planets" better than the humble cloud on the brink of getting a bit feisty? OK, so that one's a joke.
Part 2 is all about DC and (imo) has some much more interesting choices than part 1. Stay tuned...