What two dinosaurs would you mash together?

Hmm..... I'd combine....

Utahraptor Ostrommaysorum

And Pteranodon Longiceps (I know it's not a dinosaur):

Think about it: A Utahraptor with a head crest, a short, sharp beak (with Utahraptor's teeth near the base of the mouth), and wings. You can't run OR hide now...

That would be a terrifyng and beautiful beast sci-fi king. ;D

so along the lines of this?

Spinosaurus

Tyrannosaurus 

a spinosaurus sized T. rex with humongous arms and three deadly claws and finished with a sail 

UNSTOPPABLE!!!

Probably Carnotaurus and Dilophosaurus (the Jurassic Park version.) think a Carnotaurus with the camouflage ability with a frill and the ability to spit poison. It would also have long arms instead of those short ones with four claws. It would be an unstoppable threat.

I would have done T.rex and Spino like Allotitan, but I'll do something a bit different. 

Daspletosaurus

Allosaurus

The size, strength, and smarts of a Daspletosaurus combined with the arms, claws, and speed of an Allosaurus. I'd name it Gorgodromeus meaning fierce runner.

@Somthing Real interesting combination! Although I would have changed archeopteryx to sinornithosaurus, lure you in with the cuteness the get you with with the venomous bite! >:D

I would do a combination of a Spinosaurus and a Pteranodon. I would be huge and would fly. It would be perfect combination for me. It would look like this.

Rex and Spino for me. Spino's arms, Rex's strength, the ability to swim (better than half decent that is), Rex's all around appearance, and Spino's sail. 

Rex and Giga, oh wait, that already exists, it's called Tyrannotitan. Anyway, it would have the intellect, torso, hind legs, jaws, teeth and binocular vision of a T.rex and the arms and speed of a Giga.

@Mr. Happy, would it look like this?

Kinda, but bigger arms, a bigger head, and if it had a collar, it would have spikes.

Whats bigger than Pterospinosaurus and swims? Pterospyrannolodon.

I would mix Deinonychus and Acrocanthosaurus its killing claw would be as long as a mans leg it would have a spine taller then a man and it kill evrey thig.

sorry it would kill evrey thing sorry if i spell stuff rong