Thank you MrSnuggles, your post has finally compelled me to register after several years of lurking
My most memorable trip in a 747 was travelling from LHR to New York with a friend (who coincidentally was half Swedish) and after the friendship, err, 'blossomed' in NYC we joined a certain club on the return trip.
The BA cabin crew then gave us a carrier bag full of minatures to celebrate.
Although if I was given a choice I would prefer to travel on the A380, I will always have fond memories of the 747 and I admire your willingness to fulfil your desire (as you never know if you will get another chance... I know that I haven't).
As for a destination, I would have to second St Maarten, especially if I thought this may be my only chance to be on a 747.