I think she definitely loved him, but not as she loved Angel. I just read this other thread with Buffy quotes and in one she said she had loved Angel like she won't love anybody ever again, so I guess she feels for Spike, but not as strong as for Angel.
And even in season6 I think she loved him. Just look at her face when she sees Anya and Spike getting it on at the Magic Shop, she was just so hurt.