Good outlet for amplifiers

I have a circuit in my listening room for my amplifiers and it uses a dedicated ground.  Right now I have two duplex outlets connected - and I use the primary outlet (first on the run) for the amps (reserve secondary for subwoofers if needed).  I would like to install better quality outlets for this - two duplex, set up for a dedicated ground.  I could see spending $100-$200 per duplex, if that gets me something decent.  I want it to grip the plugs well.  Recommendations?

PS - I'm running two VAC Phi-200 amplifiers (200w tube amps, KT88)