I have a pair of AR (Acoustic Research) that works well. They are 900Mhz and interference is not a problem. Of course my cordless phone isn't a 900Mhz model, so that may be a factor.

I think interference is pretty much a crap shoot depending on your environment. I'd go to Cnet.com (or elsewhere), look at the reviews, and buy from someplace that doesn't charge huge "restocking" fees if they don't work well in your environment.

Another thing to consider is your receiver. Some receivers shut off the speakers when the headphones are plugged in, and some don't. This would determine whether or not you can leave the transmitter plugged into the headphone jack or not.