1S1DX from April, 1979
One of the most difficult "new ones" I've ever worked, due to my crummy station at the time. 20M SSB at 3 AM local time.
1S0XV from April, 1990
DXpedition by now-infamous Romeo.
This one first worked on 10M CW with 40 watts output. Amp wasn't warmed up yet, so called and made the QSO with just the exciter, power level set to drive the amp.
9M4SDX from March, 2007
A new one on 40M.