it all depends on what program you get
reason doesn't use vst's etc but it's a great program and can be re-wired into other progs so you utilise it and it enables free wiring like no other program can. reason is great for writing drums in
fruity is a good program but i just dont like the layout of it and the way there's so many fuckin windows
pro-tools is a brillaint program but the midi on it is nothing like the other progs (yet, as digi design are always updatin pro-tools)
never used cubase but it's a dance music standard these days but i hear is quite difficult to use
i hear acid is good, as is ableton
i know nothin of the sonar programs
hope this helps a bit