Do I have enough power for a good quality sound?

Krksures4,
I think the answer to your orignal question ties to whether you are talking about listening to 2 channel or 5.1 music. If most of your serious music lstening is to vinyl or 2 channel digital, then obviously, your are fine with the MAC & 801s. IMHO, the issue of 75w for center & rear channels will likely come into play when listening to film/tv/etc. Since most signal to center channel is dialogue, & the rear is mainly sound effects, you don't tend to need quite as much power there. Sure you might get a bit of audible clipping when a helicopter "flies overhead", but IMHO--so what. Center channel spoken dialogue is not taxing on an amp, relatively speaking.
OTOH, if you expect to invest heavily in SACD 5.1 or DVD-A and multichannel serious music is your key concern, then a little extra power might be called for. You could always hook the MAC up to center or rear for a test list'en w/o mains in the mix.
Personally, I think we're years or decades away from enough good multi-channel music to consider multi-channel for anything but movies/tv. Thus, for me the solution is a cheap HT rig, and a good separate 2 channel music system. Therefore, I'd suggest saving the $ and stick w/the 75w. Cheers, Spencer

Keep in mind that you have to double the wattage to gain 3db. You have to increase 10db to have a "perceived" doubling of volume.
With that said, you won't notice much of a difference until you at least double the wattage. With 87db speakers, I'd be tempted to go with at least 200wpc.
Remember, that if you begin clipping with the 75watts, your true output will decrease greatly due to just a few dynamic peaks. I like to have a lot of "headroom".

Spencer, you have pinpointed my dilemma: whether or not to get into SACD/DVD-A stuff at this point. I think you are right to point out the room for improvement and standardization. Yet I am also looking to enjoy whatever SACD/DVD-A have to offer with current technology, hopfully at a nominal cost. So many varieties of recording technologies are out there, and actually I am happy to see them battling things out.

That's fine, and doesn't need to cost much. Get an inexpensive uni-player, or at least an SACD player, and stick with the Rotel amp. If 90% of your listening ends up staying 2 channel, then keep investing your money in the parts of your system that affect 2 channel. Cheers,
Spencer