yea it would kinda suck to not watch the first series first
season 1 is lame, but essential
season 2 is lame, but essential, and you realize some big nonsense is about to go down
season 3-5 are pretty good.
season 6 is lame, and nonessential. It's mostly a filler season.
season 7-8 are filler seasons. meh.
season 9 is like 7 episodes? xD go watch it so you know what happens before...
season 10 (shippuuden) totally rocks.
original series went to 220 episodes, and shippuuden is current on its 33rd episode.
I watched til 100 dubbed, then switched to subs after that