Just when you have heard it all.....the "new frontier" looks like digital HF communications. Still in the "beta" stage, it is gaining a lot of interest and sounds like it might be the panacia for HF. If you are interested here are some links for you:

eHam.net DRM Forum:
http://www.eham.net/forums/Digital/171
Excellent discussion and description.

http://www.qslnet.de/member/hb9tlk/
Download site. HB9TLK wrote the software for ham use.

http://www.qslnet.de/member/hb9tlk/hamdream_setup.htm
K0PFX’s site; another excellent step by step