Bluetooth has pros and cons. Pro is that it is cheap. Cons include distance - typically 10 meters/30 feet - and success stories seem to be a bit difficult to come by.
GPRS? Possible, but not cheap, and I'm not sure that feedback is possible.
Others include XBee (what I'd use), WiFi, 433 and 355 MHz RF, etc. Cost, range, volume of data to be sent, need to receive data, and criticality of lost data are all things to be weighed.