I'm heading off on a trip soon with another person. I have heard (no pun intended) that walkie talkies are a great way to keep in touch. Who uses em' and any recommendations of which brand or what to avoid etc...
By walkie talkie I assume you mean bike to bike radios or PMRs?
As a bike instructor I have used PMRs for many years to communicate with students - I use an IntaRide IR803 which has been absolutely rock solid and reliable for nearly ten years. There are cheaper options that you might consider as you will not need a hi-spec radio for your needs. IntaRide have quite a selection so I suggest that you give them a call.
You will also need a headset, harness and PTT (Push To Talk) button to mount on your bars if you go wired or they have a Bluetooth solution - depends on your budget.
That is my thinking, I have Schuberth SC1 comms made by Sena, and they say you can talk to the bike in front a KM away, not tried that yet, but works well with pillion, sometimes to well.
I have an interide 803/ Autocom setup which are permanently hard wired to the bike with an external aerial. I also have a couple of Kenwood Funkey radios which I loan to a mate who also has Autocom. The funkeys take AA batteries which last for weeks.