Just to clarify some issues about amp power. While the warnings about damaging your speakers due to excessive power have merit, it is very unlikely.
In almost all cases (certainly most of the cases that I've seen) damage to the voice coil of a cone driven speaker is caused by insufficient power. Though it seems oxymoronic, it happens all the time.
When your amp runs out of power, it will clip the signal. This turns the nice sine wave into a nasty square wave (OK, an approximation of a square wave). Moreover, the square wave has a lot of high frequency harmonics in it. Two things happen.
One, the voice coil of your cone speake is extended for the length of time it is trying to reproduce the signal. This causes the voice coil to heat up. It's the moving back and forth of the voice coil that helps cool it. By leaving it extended for long periods (relative to normal operation) the heat can't dissipate and the voice coil is in danger or burning out.
Secondly, the high frequency harmonics stress the voice coil while its already in this vunerable position. That couple with the first issue cause real problems.
The clipping characteristics of amps vary. Tube amps do not have that problem. They clip smoothly. Single ended amps also have much nicer clipping characteristics though there are very few high power single ended transitor amps on the market.
So, enjoy your powerful amps and do not worry about speaker damage. Your ears will tell you long before your speakers do that you're playing your music too loud.
