This is a subject that's hard to recommend for, because it's largely based on personal taste.
Most surround sound receivers are 6-8 ohm stable, so it's not really that hard to pick out speakers for the amp. I'm sure you're familiar with ohms law? I'll give you the benefit of the doubt and assume you do, let me know if you don't.
Picking out the speakers are where the majority of the "personal taste" factors in. It's not hard if you're not too worried about "the perfect sound" but I'll give some examples.
There are certain materials that some people prefer over others. especially tweeters.
Tweeters:Some people like Aluminum because they think it sounds "sharp", Silk because they think it sounds "Smooth", Ribbon because they think it sounds "True and Accurate" and has a larger radiating area, perfecting imaging. Some people like Pro Audio style "Bullet" or "Horn" style tweeters, mostly because they're extremely efficient (get louder with less power)
http://en.wikipedia.org/wiki/Tweeter.Midranges: some people prefer the sound of 3 way speakers over 2 way. Essentially, it's a driver that's crossed over below the tweeter, and above the woofer. The reason being is that sometimes the lowest frequency and tweeter can accurately produce, and the highest frequency a woofer can produce, don't overlap or even meet. The midrange is there to fill in the gap. You've got PA style midranges, and regular style. Again, the PA style is very efficient, the regular style is usually thought of more of a smooth and accurate sound.
http://en.wikipedia.org/wiki/Midrange_speakerWoofers:This subject is less "cut and dry" than the subject of tweeters. There's really only three major subdivisions. PA Style, Midwoofers, and Woofers. The PA style is very efficient, the midwoofers are used to play the frequencies between the tweeter and the subwoofer, or the woofer is used to play from the tweeter (if possible) or the midrange, down through the bass.
http://en.wikipedia.org/wiki/WooferSubwoofer:Used to pick up the lower octaves (usually 80Hz on down), from the lower octaves of a bass guitar, to the kick drum, down into the subsonic "rumble" in movies.
http://en.wikipedia.org/wiki/SubwooferAmps:I'll stick to the 3 most common types.
Class T (Tube Amps): Some people like tube amps, because they feel that they can have a more "Warm" sound to them. They are often expensive, and hard to find with high power outputs. Any amp you find with a high output is ridiculously expensive lol. tube amps are most prominent in electric guitar amplifiers, very high end home theaters, and very high end sound quality competition vehicles.
http://en.wikipedia.org/wiki/Tube_amplifiersClass A/B: The most common in Home, Car, and budget PA amplifiers. These are usually mosfet amplifiers designed to try and "mimic" class A/T amplifiers. These are usually some of the better "watt per dollar" amplifiers. You really do get what you're paying for in this area, they can range from cheap and of bad quality, to moderately priced and of moderate quality quality, to kinda expensive and high quality.
quote Wikipedia
Class AB
Class AB is intermediate between class A and B, with better power efficiency than class A and less distortion than class B.
The two active elements conduct more than half of the time, producing less cross-over distortion than class-B amplifiers. In the example of the complementary emitter followers, a bias network allows the quiescent current to be adjusted, providing an operating point somewhere between class A and class B. Sometimes a figure is added (e.g., AB1 or AB2) for vacuum-tube stages where the grid voltage is always negative with respect to the cathode (class AB1) or may be slightly positive (hence drawing grid current, adding more distortion, but giving slightly higher output power) on signal peaks (class AB2). Class-AB circuits with large negative feedback provide excellent distortion characteristics with good power efficiency, and are widely used for solid-state amplifiers.
Class D: Most prominent in car audio, mostly subwoofer amplifiers. These are mosfet amplifiers like the class A/B but they have a different power managing system. They are typically more efficient than class A/B. audiophiles typically critique the sound quality of them, but like class A/B you get what you pay for here too. Some of the most recent trophy holders in car audio sound quality competitions used class D amplifiers.
http://en.wikipedia.org/wiki/Switching_amplifierHonestly, if I were to do a home theater, I'd go with a nice class A/B or class D amplifiers. Crown is a really good brand, they make quality PA rackmount amplifiers that are well revered in the Home Theater and PA communities.
If this is all above you head, and you're looking to piece together a system, I can recommend a few options!
