I would say Gaara... he can create a sandshield that can absorb the equivalent of an H bomb.
I guess it all depends on location though. He needs to take a little amount of time to create more sand than that which he carries (which he can do from soil) though he always carries enough to create a full body defensive shield that is stronger than steel.
I would go for Gaara, either way though. he doesn't even need to know about danger for his defences to activate.
Green Goblin Depending on location he might he's flight craft flies so he has a advantage plus its fast that can go faster than Gaara's sheild before it gets to block. That's when Goblin would go for a crucial hit, maybe a bomb or getting stabbed with he's aircraft. Yet again depending on his aircraft.
Gaara He has the upper advntage in this fight to me. If he could GG off his aircraft he has this fight in the bag. That should be quite easy using his kunai's or jutsu's. Then GG would be owned then, Earth Coffin GG and he's crusghed.
I'd say Gaara has the better advantage of this fight
well unless otherwise stated you go with the current version, so gaara is without the demon inside him. They haven't shown what this version can do, I believe he would be much less powerful. I haven't seen gaara do anything except attack with sand, and don't know if he has the automatic defense without the demon anymore.