Wireless for Arduino - Sub GHz

I've been looking for wireless modules that play nicely with the Arduino, but XBees seem to dominate. These all work on 2.4GHz, which is a forbidden frequency for this project.

It needs to be able to transmit and receive, and should preferably be interfaced with through some sort of serial link with the Arduino.

Does anyone have any recommendations from a previous project?

Something like this works well.

I tend to like these better though

They can also for Star and Tree networks to bounce data about.