While the C130 / A400M route would be top in terms of the 'military flying', and variety that it would entail, I wonder if turning down the C17 or Voyager (hypothetically speaking) would be a sensible decision for the long term, considering a transition to airline flying in later life. The difference between turboprop / turbofan experience seems to be viewed quite significantly later on.
It does beg the question as to why you would join the RAF if you didn't want to do military flying? Even going C-130/ A400M I would suggest you are FAR better placed than FJ & RW mates. A Four Engined, Multi Crew, IFR, Glass Cockpit aircraft is still a massive tick. By all accounts TurboProp vs TurboFan is just a couple of flights to get used to the fact that you need to give it a minute to think about giving you power and that you can go much higher and much faster!