Can anyone recommend one that isn't too hard to work with?
I can only speak with limited experience. We're using a couple of the Bluetooth Bees from Seeed. Because they're a bee, we need some kind of interface hardware so are using the Bees shield. I understand the chipset is common across a lot of these modules and you can get bluetooth functionality on a breakout board which is cheaper again, and won't need the sheild.
So far I've found it very easy to work with. There are two modes, one you put it in to set it up and one you put it in (default) for data. When in setup mode you can get it to pair with another device, then the simplest way to work with it is to set it to automatically connect to its paired device on power on, when the connection drops, and when the other device returns to range. Then in your sketch you don't even have to worry about the connection, just worry about the data.
In the normal mode, it's just a serial device to the Arduino, so you set it up using the SoftwareSerial library and use your regular read(), write() and available() methods for communicating with the paired device.
Hope this helps (if not for your selection of hardware, at least to boost your understanding of the ease-of-use side of things)