I'm no RF guru. On the contrary, I'm a baby. Hence, I need a little... "help". I'm using a transciever based on the Nordic 2.4GHz chipset...
These are available at http://www.sparkfun.com/ (along with lots of other very useful items). I bought some 3rd party 2.4GHz transciever boards from them for $20, which is plenty to get me going. I plan to eventually use both of these in my designs, and throw on power boosters for greater range with my own PCB's.
Until that time, I'm doing good as it stands. I considered Zigbee, such as those chips available from Chipcon, but they're a bit expensive at $9/chip and need external parts. However, they are true Zigbee parts and have integrated 128 bit encryption, which is intiguing. Still, I'll hold off on that. I'm not trying for a secure network, and I doubt I'll be hacked running my R/C car around since it's not 802.11b (great speed, range, oh dear look at that power drain...)