It is possible that the headphone out on your laptop isn't up to scratch, so YMMV.
What I use is a Soundcraft compact 4 mixer, with all analogue connections- the record and playback ins/outs go to my laptop, the monitor output goes to my hi-fi/speakers. I can plug instruments into the mixer and monitor them from its headphone outputs or through the main speakers, regardless of whether the computer is on or off. I can also record or monitor through software while the computer is on (running through the separate 'playback in' section of the mixer).
It seems to me that if you went for something more like what I'm describing, as opposed to the 8 in/1 out approach of the Phonic, you could use the TonePort as your I/O from the computer (bypassing the headphone output issue) and any routing to speakers/headphones/recording could be done at the mixer. Or, if you got a USB/FireWire mixer you could do away with the TonePort. Does that make sense? All this routing makes my head hurt!
Hope that helps.