I use PPro 2 with 720p HDV from JVC HD110. My editing rig is Intel Core 2 Duo E6400 2,14 GHz and Matrox RT.X2. The system would be able to edit at least one HDV stream WITHOUT Matrox, but this way, I can get mutliple streams with CC and transitions in realtime without hiccups, and realtime full-res preview with effects on TV or monitor thanks to RT.X2’s DVI output. Or you can skip RT.X2 and invest 500 bucks into Cineform. You would need large disk space, but can edit HDV even on lowly notebooks.
In basic terms, there’s not much difference between working DV or HDV in PPro 2 with Matrox. PPro 2 alone cannot preview HDV in its own capture window, and IIRC, it can’t do automatic scene detection. Cineform or Matrox RT.X2 helps here.