Jeff, I have a five channel Yamaha 5280 receiver that is 100 watts a channel. I use it as a home theater and a stereo. I did exactly what you are asking about. I used the preouts on the Yamaha for the front left and right speakers and added a Rotel RB 991 which is a 200 watt/ ch dedicated amplifier. Why? For starters, more clean power into several speaker models allows them to reach their full potential, even at lower listening levels. I have Polk Audio speakers, and the fronts are Polk Audio Monitor 70s which are floor standing speakers and have more power handling capacity (up to 275 watts) and a greater overall speaker response 32 hz to 25 Khz, than the centers or the surrounds. The centers and especially the surrounds wouldn't be able to take that much power, and they also don't have quite the same frequency response. In movies, it just gives a little extra kick for the sound, but it also means I have a great 2 channel stereo system, and my Polk Monitor 70s will really deliver the sound they are capable of. I definitely noticed a big difference in listening to music, especially SACDs, and CDs. (not that my Yamaha was at all shabby). The Polks just seemed to sound more defined with the extra power. Many speaker reviews that you will read state that speaker X doesn't sound good unless you deliver a lot of power into it. When you get a receiver, just make sure it has preouts. Most good receivers i.e. Denon and Yamaha do in fact have preouts that allow you to upgrade to separate amps later on. I also believe that both of those are good mid fi audio choices (read, I have those receivers and I like them, and have been happy with them). Denon and Yamaha also offer lines that are compatible with many peoples budgets. When I decided to add the extra power, I read many good things about Rotel, which is considered the budget end of hi fi. They aren't Crowns (really really expensive hi fi), but they have received excellent reviews in the consumer review portion of this site, and many people who decided to do exactly what you are thinking of, loved the improvement. As for speakers, well don't get Bose, but speakers are highly subjective! It seems there are as many opinions on speakers on this site as their are members. Myself I like Polk, because I can't afford speakers over $1,500 a pair yet, and Polk has a budget line, and I really love the sound. My secondary system has Cambridge Soundworks, which I have found to be a high quality speaker. I would suggest looking for speakers that have a good response down into lower frequencies (i.e. 32 hz) before there is a -3 db rolloff, becaus I notice that you are'nt planning on a subwoofer yet. You should get at least front speakers that handle a full frequency range. My only other advice is DON'T go with satellite speakers (those tiny little ones). They just cannot handle a full frequency response, so they sound horrible with music and movies when you compare them with even a good budget set of bookshelf speakers.
