LeafxCrow

I think so. I mean, Leafpool was willing to give up her entire Clan for him - her sister, father, mother, and more. She must have loved him a lot.

As for Crowfeather, I am unsure. He seems sweet and soft around her, and he even said so himself that she was kind and patient for him, but Crowfeather might have seen Feathertail in Leafpool, so it may be an echo. I am unsure.

an analysis of their characters and what I've seen from other people makes me think it was more a whirlwind romance - neither of them had experienced real, deep love before (I see Crowfeather's attraction to Feathertial as more of a crush then love, I doubt it would've lasted), and they thought what they felt was genuine.

They were both relatively young and still shaken be the clans recent move, Crowfeather was just coming out of mourning, and Leafpool, who had wanted to be a medicine cat from day one, was receiving romantic attention for the very first time.

Crowfeather had found a she-cat who closely mirrored his lost 'love', sweet, generous, beautiful, selfless, and she didn't antagonize and grate him like his clan members did. He was already unhappy in Windclan, he even tried to run away as a kit because he had no friends.
Leafpool had been put on a pedestal from a young age, as a medicine cat and as Firestar's daughter (remember Squirrelkit was so jealous of the attention she got, she put ants in her nest?). Her whole life was a series of rules and taking the backseat (squirrelpaw going on the journey, leaving Cody behind, not being able to help Mothwing with her troubles). Suddenly there's this tom who's a bit dangerous to be seen with, thinks she's beautiful, and tells her he loves her, a chance to grasp her fate and make it her own.

Crowfeather would've known about Leafpool from Squirrelflight on their journey, and as a medicine cat, he probably would be more likely to have known her from gatherings and interclan gossip in general. It would've been easy to project his feelings for a lost Feathertail onto a she-cat who resembled her personality, even if they hadn't been close before, hence the "you walk in my dreams"

Not to make Leafpool out as little more then a rebellious teen, but I do feel that rebellion had a lot to do with her leaving the clans. Like I said, she'd wanted to be a medicine cat from a very young age, she never would've allowed herself to fantasize about a mate or kits, she always knew the rules and the sacrifice. This was her first brush with romance and it consumed her, as it would to anyone, someone thinks she's special not because of her heritage or her job, but because of her.
I don't think it was a mate she needed, I think it was a good friend.

They barely knew each other before the romance, barely spoke two words. It couldn't have been love