I find it between the two. I don't believe he is attracted to his mother, I think he is more bewildered by her sexual desires that he would have thought to be dormant by now. It seems implicit in the text that the court with Claudius as King is far more "lively" than before. Hamlet comes home to see this drastic change and cannot fathom it.
The ghost instructs Hamlet to leave his mother to heaven to sort out. But he is preoccupied with her, and his rants about woman's deceit, though spoken to Ophelia, seem to have Gertrude in mind as well.
The scene in the Queens Closet, not the bedroom, but her innermost space, is an appropriate time for Hamlet to let loose his vitriolic temper.
There is no doubt that there is a sexual undertone to the language in their exchange.
"I shall wring your heart if it is made of penetrable stuff."
she has done such an act that , "blurs the grace and blush of modesty."
"at your age the hey-day in the blood is tame."
On it goes, until the ghost says, "this visitation is but to whet thy almost blunted purpose." (Don't try to force your "purpose" there, it (her heart) is hard as stone.
Finally, she says he "hath cleft my heart in twain" (Oh... so it is penetrable... or she is lying, believing him mad)
I don't find the Gibson treatment too responsible, but certainly Hamlet is floundering over the appearance of sexuality in his mother as much as the sin of murder.
Here, here, Amy! I'm so relieved to hear someone else say this...I, too, feel that this "repressed sexual longing for Gertrude" is nothing but poppycock. Hamlet is so disgusted with his mother's marriage to his uncle - the Ghost probably helped that by reminding him of the "royal bed of Denmark" becoming a couch for luxury and incest! But Hamlet truly is disgusted by this, and I don't see anything in the text that indicates that he's disgusted because he didn't get a chance at Mom himself.
Later in the play, right after he kills Polonius and the Ghost comes back to remind him of what his true purpose should be, Hamlet tells her again not to go to his uncle's bed. He's just gotten done railing at her for sleeping with Claudius, but nothing there (that I can see, anyway) shows that he's doing this out of jealousy. He's angry and furious with her for committing what he considers to be such a heinous sin, and it takes the Ghost's reminder to calm him down and remember that he's supposed to be after Claudius.
Macbeth said it best, "It is tale, told by an idiot, signifying nothing!"
Hamlet is not repressing the urge to seduce his mother. He is struggling emotionally and spiritually with the truth of the ghost's story and once convinced, the best method to carry out the revenge. Although the bedroom scene with his mother has often been interpreted as questionable, it is my belief that he was truly in love with Ophelia. Had things been different, she would have been a princess.