Electric or Digital Piano is a good choice. Here are some key points you need to know:
- Go for the most number of keys: 88 keys is the standard.
- Hammer-Action or Weighted Keyboard is very important since most training are traditional, like the Hannon Exercises which includes proper hand gestures, positions, etc. Here for more Info.
- Metronome Feature is also very important. But no worries, almost all e-pianos today have metronome installed on it.
- Velocity Sensitivity - the harder you press, the louder it sounds.
NOTE: BEWARE OF THE CONTROLLER KEYBOARD Unless you are familiar with it and knows how to use it, then go. But learning how to use it has a lot of technicalities that you should know. It is not a kind of "Plug-and-Play" keyboard.
http://madsenstudios.com/info/a-guide-to-buying-an-digital-piano/