Thanks for the respone guys. Feel like I am finally getting somewhere.
With the system I am looking at editing 2 main formats.
PAL SD (broacast not DV)
1080 HD (anywhere from HDV to SR (SR is obviously huge data rate))
Probably using the Decklink Pro HD card so all will be in 10-bit.
I am directly comparing it to a Similar window based Premire Pro system.
Also seeing if it is justifed to spend more money on a system like:
Matrox AXIO
Leitch VelocityHD
Smoke
DVS Clipster