I think the first thing you need to decide is Stereo or Surround Sound?
Surround Sound is great for movies, but less so for music.
Stereo is great for music, but less so for Movie. Though I get by just fine using a stereo for movies, but I've got some pretty big speakers.
Another advantage of stereo, is you get higher quality equipment for a fixed amount of money. With surround sound, though the Surround effect is good for movies, your money is spread pretty thinly across a lot of speakers and a lot of amplifiers.
In terms of power, for stereo, as long as you are 45watts/channel or above, you are fine. With AV/Surround amps, virtually all of them have plenty of power, so that's not a problem. Ideally, for stereo, we want to be in the 60w to 80w range, though if you can push up to 100w/ch, so much the better, but with more power comes a higher price.
Good places to shop -
Crutchfield.com
MusicDirect.com
AudioAdvisor.com
Frys.com
Also, you can find some manufacturers who have their own EBay seller sites -
Harman Kardon / JBL / Infinity can be found here -
harmanaudio | eBay
Polk Audio Speakers here -
polkaudio | eBay
Direct from Polk Audio, look at the "Monitor" series of speakers -
[PAIR] Monitor 40 Cherry Bookshelf speakers Polk Audio | eBay
[PAIR] Polk Monitor 50 Cherry High Performance Towers | eBay
[PAIR] Monitor 60 CHERRY Towers from Polk Audio | eBay
[PAIR] Monitor 70 CHERRY Towers from Polk Audio | eBay
If you are looking for bargains on Yamaha amps, several can be found here -
usabargaindeals | eBay
Personally, I would recommend a stereo over a surround system.
For course, there are the good old stand-bys of BestBuy.com, and believe it or not, Walmart and Sears have a pretty good selection of audio equipment on-line, 100 times more than you will ever find in their stores.
Connecting the MAC is not that hard, initially a simple cable is all that is needed. If the MAC has some type of digital output, then later you can add an external DAC (digital to analog converter), but that can wait for now.
Having remote control from another room is going to be difficult, but I think if you have an Apple Airport Network, or maybe Apple TV Streaming, then you can access the files on your computer using other apple devices like iPod, iPhone, iPad. In a sense, the touch screen and display on the iPod act as the interface to the music on your computer.
Good general purpose amps would be from Yamaha. The AS300, AS500, and perhaps the AS700 are all integrated amps that would fall in your price range. The Yamaha RS300/500/700 are AM/FM Receivers, again, they should fall in your price range.
The Yamaha R-S500 has 75w/ch AM/FM and run roughly US$350 -
Yamaha R-S500 Stereo receiver at Crutchfield.com
The very nice Polk Audio Monitor 70's are sold direct from Polk at a substantial discount -
[PAIR] Monitor 70 CHERRY Towers from Polk Audio | eBay
That would be a system that most would envy, and it would do an excellent job for both music and movies. And this system comes in at well below your budget at only (roughly) US$700.
Though of course, that is only a very small cross section of possibilities. I suggest you browse around the Sites I listed above, and just get a general ideal of what is in the market.
If the Monitor 70 are way too big, though I don't think they are, then certainly the Monitor 40 would do a very good job in a slightly large bookshelf speaker.
In general, brands of amps/receivers to consider are NAD, Marantz, Cambridge Audio, Yamaha, Denon, and Outlaw brand amps, though the Outlaw are going to push beyond your budget. Onkyo stereo amps are also worth considering and several models will fall in your price range as well, though I think I personally prefer Yamaha. Pretty much all these brands also make good AV Surround amps.
Again, the more you can refine your requirements, the better we can help you.
Steve/bluewizard