I was driving my Martin Logan Aerius i with an NAD C340, and just recently upgraded to a tubed VTL IT 85. The difference between these two amps is HUGE HUGE HUGE. My speakers have become SO musical. Veils and veils removed. Mids are MUCH richer, fuller... the NAD really sounded thin in comparison. I have to just stop and stare at my speakers sometimes, i'm so amazed at the music coming out of them with the VTL.
I also listen to a lot of non-classical music, and I now understand how pace, rhythm and timing really can change with a different amp. The music has really jumped in terms of excitement and energy with the VTL.
The IT85 is an integrated amp, rated at 80 wpc, but it is more than sufficient. I never turn it up past 12 or 1. I guess what I'm getting at is don't worry too much about getting an amp with some huge power rating. I'd bet 150w for each channel would be sufficient. My Aerius recommends 80 to 200, so I'm right at the bottom recommended setting, and the amp totally blows away the 100w rated NAD in terms of power.