I think the three main paid ones would be:
Zenfolio
Smugmug
Photoshelter
If you read through all the details, there are subtle differences but they all do about the same thing. I studied them for about a month and went with Zenfolio:
Zigzag Mountain Art but they all have good points and bad. So far I'm mostly happy with Zenfolio but there are lots of threads with people who want something changed and it doesn't happen. Same as on Smugmug or Photoshelter.
Then you also have 500px, which I'm not quite sure what they are trying to be, a stock agency, photo host, ??
And then of course you have Flickr, I only have the free version and do not use it much. I understand they have been having a lot of problems uploading lately. I tried to upload a series of lens test pictures and it took almost two days to finally get them all right: Here is the link to the album on Flickr:
https://flic.kr/s/aHskx21uhp