Everyone is going to have their own opinion. Teeth is one of my least favorite songs, but it's some people's favorite. I love Again Again but most people hate it. The only major complaints I have are:

too high on the list:
9. Teeth
10. Highway Unicorn (Road to Love)

WAY too low on the list:
35. Scheiße
38. Bloody Mary

For the record, I think Paper Gangsta is her worst song

My Top 20:

1. Bad Romance
2. Paparazzi
3. Marry the Night
4. Scheiße
5. Poker Face
6. Alejandro
7. Monster
8. The Edge of Glory
9. Hair
10. Judas
11. Dance in the Dark
12. Bloody Mary
13. Greatest
14. Americano
15. Living on the Radio
16. Telephone
17. So Happy I Could Die
18. Yoü and I
19. Born This Way
20. Just Dance

There are times when I think Scheiße or Marry the Night are better than Bad Romance, but I have over 800 plays on my iTunes for Bad Romance and I don't think Gaga will ever top it.