Amplifier Weight. A Factor?

Sbrtoy is right.The monster SS amps will become dinasours if they are not already.Many of them also sound apalling-some are reasonable, so the belief that heavier is better is a flawed generalisation.Most lightweight chipamps and the newer breed of PWM /digital type amps like NuForce sound better,run cooler and are comparatively very light.Not to mention much cheaper.Audio retailers hate them for this of course.
Tube amps are a different matter however,although I have heard some very ordinary sounding monster SETs that are not as good as a much lighter PP types.
Let your ears do your buying,not your eyes or muscles.

There are many high efficiency speakers out there.No more need for me to go for big heavy amps.Anyway a lot of the watts are wasted as heat,in cross-over and to adjust the sensitivity of the drivers.

As Macrojack mentioned, it's all in how you start off. If you buy inefficient speakers you wind up with large heavy power amps. With my highly efficient speakers, my analog power amp only weighs 20 lbs and puts out 60 watts and can bring the music to concert hall levels, well almost.

Jtgofish, if it`s one thing most Class D amps aren`t is cheap. Very poor bang for the buck.

If you've got huge amps....make sure you plan carefully where you plan to put them, or have an understanding friend to help you move them. I have four Pass Labs X-600 behemoths....impossible for one guy to safely move around. Big and very awkward to handle at 150 lbs each. I keep a six-pack of beer in the fridge as a reward for friends to help me move stuff around.

The fact is, if you've decided to go with big stuff, you'd better factor in having someone to help you move it around. There is no way I would ever consider trying to move any of my stuff around without help....too dangerous because of personal injury and the huge potential to deface your equipment.

Get your calf gouged by a heat sink fin of a 150 pound amp...you'll wise up quickly.

I always keep two pair of work gloves handy...one pair for me and one for my friend that's helping me.