What is the best transmitter/receiver to use with an Arduino RC?
That depends largely what is controlling it

Some options include:


wifi, if you have an expansion board, from a PC or phone (spec says: 66ft/20m)
bluetooth works great, directly from your phone (spec says: 32ft/10m - 320ft/100m)
433mhz ASK transmitter/receiver from another Arduino or other hand-designed circuit (spec says: 100m/320ft)
Infrared receiver - from a TV remote! (range unknown, depends on remote &amp; conditions; would not trust it 10m outside without testing).
Cellphone network - longest range (nationwide!). If you get a cheap android to do some of the work, you can use the phone's compass &amp; gps &amp; extra processing power, as well as the camera(s)!
Remote control. I know you said you lost yours, but in case someone else is looking here, you can hook up an rc receiver to an Arduino fairly easily. https://www.sparkfun.com/tutorials/348 for more info.


Many of these ranges specified will depend on the antenna. If your car can tell it's lost signal, then it can stop; otherwise you have to outrun it, or wait for it to hit a wall.

Edited to include cellphone network, and added ranges to options