I second HKG!!!
GIG is $140 visa fee and done in advance--90 days lately

EZE might be worth the fee if you'll go enuff times--food and wine are cheap but digs can be high. You can return and see spectacular Iguacu Falls another time or just eat steaks a few times!)

What about Ecuador--it's a pretty HOT destination in the trav mags?

So--HKG--DL has nonstop DTW or the NRT cnx (that's really brutal, but I know you've prob had worse...)
You can get some great room rates--accor has a few places you can use DL discount and the Y hotels are supposedly very GOOD. Food is incredible--transport is cheap--3 day pass:
MTR > Airport Express Services > Airport Express Travel Pass

You WILL be tired but if you do the DTW--3:30 pm arr next day 9pm, the rtn is 10am back same day noon
I just researched new stuff for our trip in Feb and have been once before. Of course, Nick has the skinny on all the details and then some!
Good luck!!
PS--I always vote for Prague or Bud over anywhere else in EU--Boss and I favor them! He does FRA alot--and is there now for 2 trips.