I bought this CD in early 2006 and listened to it obsessively for the better part of a year. The collection is excellent, featuring some of the most memorable songs to play on Buffy, and it makes a great companion to the original Buffy Soundtrack.
Although some of the songs are easy to connect with certain episodes, several of them are harder to place, and thus I present this handy episode soundtrack guide, gathered from John King's note on the CD and various internet sources: (episode number, episode title)
1. Buffy Main Title Theme (new recording by The Breeders)
2. Bohemian Like You (5.11, "Triangle")
3. Everybody Got Their Something (6.6, "All the Way")
4. Dead Guys With Bombs (3.13, "The Zeppo")
5. Key (5.14, "Crush")
6. Sound Of The Revolution (6.15, "As You Were")
7. Ballad For Dead Friends (1.2, "The Harvest")
8. Blue (7.7, "Conversations With Dead People")
9. Pavlov's Bell (7.8, "Sleeper")
10. That Kind Of Love (6.18, "Entropy")
11. Sink Or Float (7.13, "The Killer In Me")
12. Still Life (7.14, "First Date")
13. Black Cat Bone (6.10, "Wrecked")
14. Just As Nice (6.6, "All the Way")
15. I Can't Take My Eyes Off You (5.6, "Family")
16. The Sun Keeps Shining On Me (6.6, "All the Way")
17. Run Away (6.9, "Smashed")
18. Summerbreeze (5.10, "Into the Woods")
19. Sugar Water (2.1, "When She Was Bad")
20. The Final Fight (7.22, "Chosen")
Hope this is helpful! I know I was going crazy trying to figure out where some of these songs were featured in the show. ;)