Europe or Round the World?

I'm going to go away for about 2 months travelling alone on a gap year. I live in the UK. I can either choose to do Dubai, Singapore, Oz (Sydney, travel to Melbourne), NZ, (Christchurch and Auckland) and LA or travel round Europe with Interrail. Europe will be about �1000 cheaper (flights come to around �1300 for RTW). Europe would include Spain (Barcelona, Madrid), France, Sweden (Stockholm), Croatia, Austria, Germany, Switzerland, Luxembourg, Greece. I have the money for both but don't want to throw it away. Backpacking alone is common but sounds like it could be dodgy so that may be a plus for doing the cheaper option.