Unless your current amps are insufficient to drive your speakers cleanly at satisfactory volume, no. More watts can give you more headroom for the loudest parts. Remember, each doubling of wattage gets you 3dB. Not much but it can make a real difference IF you are clipping on the loudest peaks.
A very unscientific rule of thumb I use is: if you usually have your receiver's volume control well past the midpoint (say 2/3rds or more of max) maybe a bigger amp would be worth getting.
Note: What Howie did, basically, is drive his speakers with 200 WPC via bi-amping. Could accomplish the same thing with a single 200 WPC amp. Not a bad solution since you already have the amps in the receiver, but make sure you have two sets of posts on your speakers. Otherwise, you'll be "bridging" two amps if you attach them to the same posts which can destroy amps unless they are designed to be bridged.
Oh, and if you can, get one that goes to 11!
