Do you have any prior heli experience with collective systems? If not, you may want to rethink your decision for a CP. They are very squirrly and will keep you on the sticks alot - in short, a handful. Can be a discouraging thing if your bird is on the shelf waiting to be fixed rather more than in the air. But back to your question:

Extra parts: (my experience)
blades (wooden flat first then symmetrical)
spindles (a lot!)
main shaft w/ drive gear
retaining pins
flybar
main frame assembly w/ tail boom
a few extra tail motors (they have a short life)
replacement canopy after several crashes

Hopups:
upgrade to the 3 in 1 control unit so you can add a separate gyro, and go brushless on the
motors.
a lipo battery

Just a few things I could think of off the top of my head right now. Hope this helps ya!

Mark