I say Thoroughbreds. I've ridden a lot of them & find them to be great jumpers (that's what I mostly see anyway in the jumping rings!) But then again, that's just my opinion.
I don't know much about the other breeds (never ridden either of them).
I would say TB's just bc that's what I have and i've ridden TB's and warmbloods in jumping and I just like TB's better, they seem to be more agile, speedy and balanced.
But that's not to say Oldenburgs arent good jumping, it depends on the bloodlines and body build of the horse as well. So in general it will come down to comparing one horse to another not just a breed bc Oldenburgs do have a lot of TB's in them.
Definetely not Arabians. They were not bred for jumping, and because of their high head carriage they look awkward over fences. But there is always the odd horse that doesn't fit in with the breed, of course. :]
I don't think I have ever seen any oldenburgs into high level jumping. When I look at the select few that compete at the World Equestrian Games of dressage, you really couldn't help but wonder what they might be like if someone took one of them into the right training.