I for one, was always impressed by Lyra Lerrol, the chief qualification being that she had not two, but THREE Ls in her name.
Seriously, though, there was something very tragic about that story, which cast a pallor over Superman's other loves. The idea of a love that has a shadow of terrible, inevitable doom over it - I was always a sucker for that Michael Moorcock type stuff. The Lyra Lerrol story conjured up all the right emotions: tremendous tragic melancholy, and at the same time, very real passion. The degree of frigid, Norweigian sexlessness about superhero romances (and romance stories in most media in general) made prose like Jerry Seigel's in that story all the more astonishing:
"Their kisses had such heat that it made the explosion building at the core of the planet as frosty as a glacier." WOW. I had to hose down my comics collection after that. Possibly the highlight of Jerry Siegel's writing career.
For a guy with as many girlfriends as Superman, he does not show a great deal of romantic savvy or experience. This, incidentally, is a dead-on characterization: one of the best things about Superman is his lack of subterfuge. Superman spent the entire Silver Age in trouble with women somehow, whether it was Lois and Lana performing scheming catfights or elaborate plots. Only the equally women-inexperienced Archie and Spider-Man were in as much hot water as Superman tended to be. Except during Wolfman's run when he dated Lana and stories like Maggin's "Who Took the Super out of Superman?" Superman never really wooed, never really sought to express his passionate feelings. It would not surprise me if Superman has not really been laid yet - or at least did so much later than normal.
As for Lois Lane, I really like her. Firstly because the idea of a mythic, immortal cosmic being like Superman getting together with an ordinary, mortal woman is much more beautiful and romantic than two immortals getting together (which is why Superman/Wonder Woman or Superman/Lemaris is rather boring to me). What many consider Lois's ruthlessness I think, is a very nervous way of saying she was competent. Many people are dismissive of members of the opposite sex that are manipulative, despite their other positive qualities; for this reason, many intelligent women don't like James Bond and dismiss him as a "male chauvanist" or "male fantasy projection."
It's no coincidence that Lois is best written when she is savvy and competent. Diana Dane, the Lois Lane analogue in Alan Moore's SUPREME, solved as many dillemmas as he did, including defeating through logic Szazs the Sprite Supreme, and figuring out Supreme's identity all by herself. The worst lapses in characterization have been when Lois is portrayed as an easily manipulated twit; in other words, when she isn't ruthless ENOUGH!