I'll be disappointed in her if she goes with the 'Lily love triangle' thing. It's just too cliche for my taste. Of course Harry thinks Lily is beautiful and perfect, because of her loving maternal sacrifice, but if it turns out she was so perfect all the guys in Hogwarts were madly in love with her, she'll become boring and annoying, for me at least.
Anyone ever see "Ferris Bueller"? I love Jeffrey Jones in that, as Ed Rooney, Dean of Students, who chases and chases and chases conniving Ferris, because he's the only one who's got this little punk's number, while everyone else adores him. I've always seen Ed as this poor schmoe who has always gone by the book and played by the rules and whose life is a miserable mess, while Ferris, who lies and cheats and breaks all the rules, gets everything he wants, and d*mmit, it's just not fair! Now, think Snape and James/Sirius in place of Ed and Ferris, and you get the picture. James from all accounts ran wild, broke rules, pretty well did as he pleased - and was still the Head Boy and Big Shot Quidditch Star, while Severus Snape, who was probably something of a snitch and a brown-nose, got nothing. As a life-long girl geek, I can still tell you the names of the snobby cliquish girls I knew all through school, and my feelings toward them are still not charitable. I don't think it's far fetched to think that this is all Snape needs to feed his bitterness.