Xbee & Mrduino mega 2560

Hello guys

What do I need to conect my Arduino Mega2560 with a PC on USB port over 50 -100 feet. I mean what shields, xbee modules, voltage adaptors, regulators, etc. The idea is to control my balancing bot based on Arduino Mega2560 with orders coming from my PC (Windows XP).

Thanks in advance

Two of these - one for either end:

One of these - for the PC end:

One of these - for the bot:

(Needs additional parts)

Or, as a complete package:

That's it. No voltage regulators or adapters needed.

Thanks a lot.
I didn't know what shield shaped for every module.
I think I will have the complete kit.
Ophiuco