One 240 gallon tank. Two smaller tanks would be nice, but I'd rather take care of just one big tank. More tanks is more hassle and takes up more space. A 240 gallon can go a long way if you stock it right.
2- 150's if you like rare predators. Cause they also like to eat each other. So you can keep a large amount in 2 tanks that would normally kill each other in 1 tank. But if you are just into cichlids or community fish then the 240 is for you.