I use two. One weighted Keyboard for playing keyboard parts in (VSTI's) - A Yamaha P71 (88).
I also have a Nektar Panorama P4, which I use for all my parameter/automation controlling, along with CC#'s etc on Virtual Instruments.
The pads are also good for Percussion & Drums etc. All my Orchestral Instrument parts are played in with this as well. It's semi weighted, but I prefer it for the Single line Instruments.