I feel like I'm going to have the rudest awakening when I try a HHKB, but I pray it's all for the best. When I used to use Macs consistently the one thing I really liked over the standard Windows keyboard layout was Command right next to the space bar; it gave my left thumb something to actually do other than hover, doing practically nothing.
For now, I swapped the Control and Caps Lock on my keyboard for the first time in my life, this way to prepare me somewhat for the HHKB. I'm having a really hard time with it...