Definately Angelique. They have been together for the longest amount of time and are so very close. Angelique always tries to tell herself that she doesn't love him, but she always says later that she still loves him. Like she just said, "I have hated the things you've done, Barnabas, but I could never hate you."
Also, Barnabas had the perfect opportunity to kill her as she came to him as the aging Cassandra, but he wouldn't do it. He even told Julia not to do it. And as she was dying as Cassandra, she began to fall, and he reached down and helped her. I think that in itself shows that deep down Barnabas loves her, but cannot believe it.
Spoiler...
I thought it was a beautiful scene when Barnabas watched Catherine and Bramwell in PT and realized he truly loved her. Then to have him try to tell her and, once again, fate steps in and destroys his chance of happiness. Such a sad scene, although I thought it was a wonderful ending to our final RT story.
They were definately met for each other.
-Lindsey