...@75wpc should be more than sufficient to drive most loudspeakers (there ARE exceptions)quite comfortably...unless of course you prefer "threshold of pain" db levels.

In most music(again, there are exceptions), the power used is around 5watts or even less. It's when you run into crescendos, that that those extra watts come in handy. A speaker rated @250w doesn't require an amp rated that high, it only means they can handle that much...even more for very brief periods.

That's not to say power ratings are meaningless. There are units that require a minimum power rating from the amp because of their design. The spec sheets will specify min's and max's...

jimHJJ(...sensitivity and frequency response are other important numbers...)