Connectix’s old baby Virtual PC, now in the possession of oligopolist Microsoft, just turned 10 years old. I have fond memories of the first Virtual PC running Windows 98 beta on my Mac before most of my PC friends had even tried it. Check out the commemorative story at Uneasy Silence.

Picture copied from UneasySilence.com
Among other good old Connectix jewels I will just mention RamDoubler. And yes, it actually worked fantastically, although I have heard talk that it was an incredible hack!
I had a copy of Virtual PC, which died a death when I got my G5 (the new processor broke things.)
I now use Guest PC, but I’m going to buy Parallels at some point…