Queen Zenobia of Palmyra (to me, Zenobia was
the female conqueror, I know that some people are very passionate about Cleopatra bearing that very title, but the truth is that Cleopatra knew that it was too unrealistic for Egypt to defeat Rome, and therefore she worked within Rome's power structure - thereby giving advance to herself, her family and her people - however smart that is (and it really is), it doesn't make her a conqueror (nor very much of a warrior Queen). Zenobia, on the other hand, was out in the field conquering her butt off, so to speak
).
Empress Matilda, Lady of the English (the first Queen of England. I love her story, she's a great female role model and I admire that she never stopped for her (and her son's) right to the throne).
Alexandra of Denmark and Maria Feodorovna (shoving these two together in one category because they were my first real royal interest. I own god knows how many books about Alix and Minnie and I never get tired of reading them. Both sisters have very interesting stories and particularly Alexandra was a very admirable woman).
Queen Elizabeth II (there's really no need for an explanation here, is there? Just the fact that I call her HM even though she technically isn't my Queen (sorry Daisy, I still love you very much
) says a lot about my admiration for her, and that certainly is an admiration well earned).
Honourable mentions: Queen Artemisia I of Caria; King Henry IV of France; King Christian IX of Denmark; King Christian X of Denmark; Princess Marina of Greece and Denmark, the Duchess of Kent; Grand Duchess Olga Nicholaievna Romanova; Queen Ingrid of Denmark; Prince Bertil of Sweden, the Duke of Halland; Prince Philip, the Duke of Edinburgh; Queen Margrethe II of Denmark; Prince Charles, the Prince of Wales; Princess Anne, the Princess Royal; Crown Princess Mary of Denmark.