for me..the best fights in Part 1 are Naruto vs Gaara,Naruto vs Neji and Naruto vs Sasuke and in Part 2 : Naruto vs Orochimaru,Sakura and Chio vs Sasori ,Sasuke vs Itachi,Naruto vs Pain and Jiraya vs Pain
I was 10 years old..but I didn't watch it seriously at that age..I only saw the first 50 episodes because that was all I could find...and I gave up..then at age 13 I found all the episodes of Part 1 and Part 2 and started watching them seriously..and now I'm 15 and I watch every episode that comes out and I read the manga