Here are the contenders:

1) Kakashi Vs Team 7
2) Team 7 Vs Zabuza, Haku
3) Sasuke Vs Orochimaru (Forest of Death)
4) Rock Lee + Sakura Vs Sound Ninjas
5) Team 7 + Kabuto Vs Rain Ninjas
6) Sasuke Vs Yoroi
7) Shino Vs Zaku
8) Kankuro VS Tsurugi
9) Sakura Vs Ino
10) Temari Vs Ten Ten
11) Shikamaru Vs Kin
12) Naruto Vs Kiba
13) Neji Vs Hinata
14) Gaara Vs Rock Lee
15) Naruto Vs Neji
16) Shikamaru Vs Temari
17) Sasuke Vs Gaara
18) Orochimaru Vs 3rd Hokage
19) Shino Vs Kankuro
20) Naruto Vs Gaara
21) Itachi + Kisame Vs Konoho Jounins
22) Itachi Vs Sasuke + Naruto + Jiraiya
23) Tsunade + Jiraiya + Naruto + Shizune Vs Orochimaru + Kabuto
24) Naruto Vs Sasuke (Rooftop)
25) Sasuke Vs Sound 4
26) Chouji Vs Jiroubou
27) Neji Vs Kidoumaru
28) Kiba + Akamaru Vs Ukon + Sakon
29) Shikamaru Vs Tatuya
30) Gaara + Rock Lee Vs Kimimaro
31) Naruto Vs Sasuke
32) Kakashi VS Naruto+ Sakura
33) Gaara VS Deidara
34) Kankuro VS Sasori

For me my faves are the Rock Lee Vs Gaara match, and the Sanin fight.

Edit: Added in the post 2.5 year wait fights. Thanks to Terra for reminding me.....