Spektrum DX6i is very good for the money.
http://www.amazon.com/Spektrum-DX6i-DSMX-6-Channel-Transmitter/dp/B004M13YI8
If you're looking to spend a little less, you can get a Turnigy 9xr. I actually just bought one recently and have it on the way. Once I get it, I'll be able to update you on it. If you get it, I'd suggest buying a programming module to reflash it with er9x, which is better firmware than what it comes with stock.
http://www.turnigy9xr.com
A bit of caution - it's almost worth it to get the DX6i to start because it will grow with you and it's very high quality. I have one of those, but I also have a Turnigy 9x, which is similar to the 9xr. The 9x with default code had a bug that cause my copter to go almost full throttle into my ceiling when I turned off the tx. Once I got new modules (frsky modules) and reflashed it with er9x, it was a decent radio, but then I realized that the contacts on the gimbals behind the sticks wore out with only a few uses. My throttle stick wouldn't go to 0 (-100) unless I pulled it down really fast. This made it a pain to land sometimes. So really, the 9x was $60 + the frsky tx module and rx module + a board to program it with USB + a programmer + miscellaneous other stuff... and now I don't care much to use it. The DX6i was $200 at a time, so it was still cheaper... but now that the DX6i is $140 on sale everywhere, it's probably the best bet.
HobbyKing sells replacement gimbals for the 9xr and it comes with a port to plug in to program it already, so I thought it would be worth a shot as I'm trying to find a good cheap radio to recommend. The other good thing is that it doesn't come with a tx/rx module, so it's a bit cheaper and offsets the cost of getting better frsky modules by about 10 bucks. If this one doesn't work out, I may order and test out the OrangeRC stuff from them to see how it is.
There are also others out there, but none I have experience with. Another good idea might be to get something used on Ebay, but then you never know what you're getting.