Using the port audio driver ensures that only one application (the Jack PortAudio driver) uses my actual ASIO driver; all other audio applications select the Jack PortAudio virtual driver as their ASIO driver. Now all of my audio applications not only share my ASIO driver harmoniously, they can all play through it simultaneously. I even have the CoolSoft virtual MIDI synth driver playing through Jack Audio via the VB-Audio ASIO Bridge driver. Once I made the switch to this setup, my ASIO frustrations went away. 
For those who would like to check it out, there are some decent YouTube videos that describe the setup process: JACKROUTER setup guide for windows 7 64bit
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