Vicki Vale and Catwoman for me.
I never saw the big deal about Silver St Cloud. The stories she appears in in Englehart's run in the late 70's are amazing. But Silver herself is really nothing special. And her romance with Bruce is extremely brief. It lasts about 6 issues:
Dr Phosphorous story - They meet on Bruce's yacht. That's it.
Dr Hugo Strange story - They have like one scene together on the telephone because Bruce is captured by Hugo, and he impersonates Bruce Wayne for the remainder of the story.
The Penguin story - Again, they have one scene together, Bruce visits her in the hospital because she was attacked by Hugo's monsters in the previous issue.
Deadshot story - Again, they share one scene together where they meet and have lunch together, and Silver is suddenly suspicious of Bruce knowing Batman. At the end of the story, after she sees Batman fighting Deadshot, she comes to the conclusion that Batman is Bruce.
The Joker story - Batman goes to see Silver because he thinks she suspects who he is. Silver denies she has anything to say to him. Silver the flees town to give herself time to think. She eventually comes back and witnesses Batman fighting Joker. After it, she walks up to Batman, confesses that she knows who he is, that she loves him, and they kiss, then she runs off and says she never wants to see him again because she can't handle his secret.
What was the big deal about her? Her romance with Bruce was way too brief. They shared a handful of scenes together, and I never felt a big connection between them. I don't know, I just never understood why she was so iconic. I think it''s because of the great stories she happens to appear in, and not because of the character herself.