Cordelia (the greatest love story that never was.. it's like a Bright Eyes song! )
Buffy (His first, but not his last - even with all that 'when I'm cookies, I promise you can eat me' business)
Darla (Bored me through season 2 of Angel but props for being the one to give us Angelus)
Dru (Kind of a weird Daddy/Daughter relationship that Freud would have had a field day with, but still)
Kate (He kept saving her which I thought was sweet)
Nina doesn't even rate for me. Talk about replacing Cordelia in an instant. He was basically using Nina for some sort of sexual relationship, never good!
(The fangirl in me got ridiculously happy when Spike was mentioned, how hot they would have been together! And if Joss is ok with implying that Dru and Darla both did the immortal at the same time, I'm sure Spike and Angel have shared... things )