After recent experiences with the digi001, I would avoid it like a bad plague that will kill you...
The 001 does have a "wave driver" which allows other app's on a PC to use 2 I/O's. I am not aware of any plans at this point of digitech making a driver that will allow other PC app's to use ALL the I/O's. This would be a major new direction from their normal proprietary nature. I doubt it will happen. digidesign wants you to use ProTools ONLY!
About ProTools LE. I would avoid it for any number of reasons. First, plugins for it are much more expensive. Second, they include some DSP on the master buss sum that makes it nearly impossible to "clip" the master buss, no matter how hard you push a mixer channel to it. This effect causes the outputted volume of the mixed stereo track to sound much quieter. It also means you don't focus in on WHAT is causing the DSP to start working. I haven't found any way of disabling this on the master buss. Maybe another PT LE user can shed some light on this. I know for sure that this DSP is include in the verson 5.3 software because I read a rather involved article on another bbs that one of the code writers for digitech shared.
I didn't find any of the editing functions to be any more involved, or better than Sonar. In fact, I didn't find much of anything about PT LE that Sonar couldn't do. I did find plenty that PT COULDN'T do compared to Sonar, such as the much more involved MIDI capabilities of Sonar.
If straight recording, editing, mixing is your goal, and you don't need advanced MIDI functions, I would suggest Nuendo over Sonar. Nuendo sounds a little better at the master buss than Sonar does. It's included plugin's sound MUCH better than Sonar's do.
All of these applications (PT LE, Sonar, and Nuendo) either currently, or will soon support OMF (open media format) which means that you can share the audio files, complete with time stamps between them. It is my humble opinion that OMF will draw more users to other applications over PT. I am surprised that PT is going to support it frankly I can understand WHY they will support it, but I think it will in the end cause PT to take a back seat to other less expensive, easier to use applications. Anyway, just some thoughts and ramblings about that....
I would go with any ol' PC soundcard you choose (I seriously doubt there is much difference in how many of them actually sound....look for mature drivers and a easy to use hardware mixer interface when choosing...THOSE two things really define the difference between most low end multi I/O soundcards...) and Nuendo. Use Sonar if advanced MIDI capability is needed.
Good luck.
Ed