OK, that is a fifth possibility. Willow conjures money, rationalizing that it is to help Buffy, when it actually is just another step toward the Dark Side.
That would be Olivia. I think the last episode she was in was Hush.
Just a note, Jenny Calendar, who was a descendent of the gypsies who cursed Angel in the first place.
Do we get to count Druscilla for their make-out scene? 
Regarding Olivia, I don’t know if it counts as a “last appearance” but she was present in the dreams of the season four finale. “Hush” would be the last time Olivia was physically present in Sunnydale.
I knew that. Sheesh. I was so worried I had her first name wrong I screwed the pooch on the last name.
Sorry, I lost this thread… I was going to say though, that we must have different ideas of what consitutes a love interest. By my own personal definition, a love interest is someone the character has a well developed romantic relationship with. The british woman who was in all of one episode doesn’t meet that, nor does Joyce since there was nothing romantic about their relationship (friendly, yes, but zero chemistry.) So…he only had one, Jenny, and it’s still not fair.
Not only that, I’ve just seen the episode where it is revealed who Jenny really is! WAH!!!
I would so do Giles! Hot, hot, hot. Super tasty. Yum.
Olivia has been in three episodes, all of them in Season 4. I know that two of them are Hush and Restless, and I think the third is The Freshman, but I’m not sure.
They changed the name to Santa Carla, but that’s all. The movie was filmed in Santa Cruz and it does a nice job of capturing the oddness of the town. There’s a part where someone asks “How are you liking Santa Carla so far?” and the kid (Corey Haim?) answers “It’s really cool…if you’re from Mars!” Probably the city council wouldn’t let the filmmakers use the real name.
Oh yeah…Buffy. I like Buffy. Good show. Watch FX reruns, Angel’s about to go evil! Angelus is an excellent villain, I’m already freaked out in anticipation.