Ham Radio Deluxe
I would be remiss if I didn't start with Ham Radio Deluxe Software. It's the world's leading software title in ham radio. It's a single integrated suite of software for:
Rig control
Logging, DXing/DX cluster, awards tracking, QSLing
Digital modes - PSK, RTTY/FSK, SSTV... and many more
Satellite tracking and communications
Rotor control
Find the software at https://www.HamRadioDeluxe.com
As far as I know, there aren't any other good ham radio software packages out there for DXing. Most of them are either really old and no longer supported... or they're complicated and scatter lots of non-integrated windows all over your screen. They're not worth your time. :)