Wise decision! Here's the order:
Kizumonogatari - Movie (supposedly coming out in 2014)
Bakemonogatari - 15 episodes
Nekomongatari - 4 episodes
Nisemonogatari - 11 episodes
Monogatari Series: Second Season - 26 episodes (currently airing, 24 episodes in)
Even though Kizumonogatari hasn't been made yet, it's the prequel to Bakemonogatari. You can watch Bakemonogatari without being confused though.