Chinchilla, I don't think season 4 was anyone's favourite but season 5 and 6 were wonderful. Lets see what did you miss from season 4...
Oh yeah, you just missed Spike being kidnapped by the initiative and Oz leaving Willow - that was the next episode.
Four episodes later one of Willows spells goes wrong (NO WAY! I hear you all scream in unison) and Buffy and Spike think that they are engaged to be married - laugh? You'll wet yourself! Especially if you just had a baby!!
Next episode is one of the best - 'Hush'. It won Joss Whedon a pile of awards and has almost no dialogue!
Next episode - Buffy and Riley get it together (I just never warmed to that relationship) and Spike discovers that even though the chip in his head means that he can't hurt humans, he can kick the sh1t out of demons. He also wears a tacky hawaiian shirt and the entire hour is worth that spectacle alone!
Then Ethan Rayne makes Giles look and sound like a demon and whackiness ensues.
Willow falls in love with a girl named Tara (really cute relationship, this one)
Faith returns and swaps bodies with Buffy. She makes a pass at Spike and has sex with Reilly.
Jonathan Levinson also returns in a fun episode called 'Superstar' where he conjours a spell to create an alternative reality where everyone worships him - they even give him his own bit in the opening titles which I thought was a nice touch.
Well, those were my season 4 highlights. Now get back to Buffy! This is the last season after all!