Do not put angels with angels - they will fight til one or both end up dying. I have seen multiple angels in very large tanks like 500g. Also a lot of angels are not reef safe.
As far as tangs go,
I've had a sailfin tang for almost 3 years. He is perfectly happy and healthy. He spent the first year in a 55g and the last 2 in a 72g bowfront. I bought a baby hippo tang the size of a quarter about year ago. He is now very big and causing problems. He killed my mated pair of bangaii cardinal last week and is eating my crocea clam. I have already made arrangements with my LFS to trade him in for credit. I thought that if I raised it from a baby and kept him well fed, he would be a "peaceful community fish" like hippos are supposed to be. But he is obviously not peaceful probably because he wants more room. Here is a pic of my setup with both tangs. As you can see, they are both very fat and healthy.