I vote for VMWare Fusion

VMWare fusion provides better support for kubuntu 8.04 than Parallels. Performance of windows on VmWare Fusion and Parallels seems to be the same. I didnt measure the perf using any tools but I just tried my lecture videos using both of them and I didnt see any compelling perf difference. So I returned my parallels and got Fusion instead. I am happy with it.