go for ms. pinky or sereto
traktor no longer supports final scratch so thats out the window.
ms pinky can be re-wired to ableton which is awesome.
as far as laptop is concerned.. ive been using a dell inspiron 9300 for 2 years with no issues.. running ableton live with a ton of fx. go for 2.8ghz or higher with at least a gig of ram.. also a widescreen(17") can make life easier in ableton.