Hey. I'm in the middle of setting up my Klipsch speakers too. I have the full Klipsch THX Ultra II set, including the two kw-120 subs PLUS the Klipsch Amp.
I'm likely going to go with CROWN amps for all the speakers. But I have been recommend AGAINST using anything other than the Klipsch amp for the subs. Firstly, I'm curious what amps and processor you went with for your front and surround speakers.. what would you change the second time around... and finally.. what did you ultimately decide on the subwoofer amp? It would be nice to have a rack full of crown, versus that one klipsch amp.. thats not even rack mountable.