Hi Tim,
Is there somewhere you have always wanted to go? If the answer to that is yes, whether that be near or far, then your dilemma is solved.
Perhaps you have an interest that could be satisfied by a particular holiday. For example if you like history, the Jordan trip I've just returned from may be for you. Natural history could be catered for on a safari, if it's scenery you're after, than the USA National Parks trip or Canada in the Fall might fit the bill.
So I would suggest thinking along those lines rather than 'should I stay closer to home or spread my wings'. In other words, pick somewhere that really appeals to YOU (and suits your budget) rather than thinking about the distances involved.
Whatever you decide I hope you take the plunge and book somewhere. I'm sure that you'll have a great time whatever you decide.
Cheers
Mike