You're really looking at two completely different families of equipment--very rarely do you find situations where home theatre is being mixed with "pro audio".
Home theatre equipment is usually centered around a single viewing screen, and is geared towards very high fidelity audio in multiple channels, as well as surround. It's also easier for the consumer to understand and interact with, since typically there is a visual associated with your media, and you're only working from a single content source at a time.
Pro audio equipment is generally geared towards flexibility, stereo audio, and enough power to carry out into a performance space. This equipment also has a very difficult learning curve if you don't already know what you're doing.
The other thing to consider is that in a live band situation, you don't really -want- everyone's channel coming out of all 10 speakers in your surround sound system. You want some sort of spatial reference for the musicians related to the audience, and you want your sound reinforcement in a location that is not going to cause all sorts of feedback from microphones.
These families of equipment are divided all the way up to professional movie theaters. Those super-high-end systems are designed for one thing: high quality multichannel audio for film presentation. Beyond that into multipurpose performance spaces and extremely large venues is all pro audio, with very complicated equipment and a focus on the raw power required to bring 1-3 channels of sound out to a thousand or more people.
It's clear that you don't have the expertise needed to deal with a complicated pro audio mixer and system, and I'm SURE your father doesn't if he's asking you to do this. I would suggest finding a great set of speakers and a fine amplifier so that you have a great movie-watching and audio-listening experience, and then adding on the equipment needed to play instruments piecemeal.
If money is no object, there are firms out there that will put together a top-quality system with the best equipment, like this one.
If you don't have 6 million dollars, some of the finer speaker brands are Klipsch and Bowers & Wilkins. For a full surround system these can still run into tens of thousands of dollars, and that's not including a suitable (i.e. equally costly) amplifier.
The next rung on the ladder (now in the $1,000-$2,000 range) is probably Harman/Kardon or JBL (Both now owned by Harman), or Bose. Bose has worked really hard marketing-wise to nail down their brand association with "high-end" and corner a consumer market. Just don't be misled to think they're the best there is.
As you come down in price, you'll notice more systems being offered as a package deal with a suitable amplifier bundled in with the whole surround sound speaker set. Sub-$500 is where you'll find all-in-one packages at Best Buy that include a Blu-Ray player integrated in the amplifier. These are easy to use, (relatively) cheap, and generally not a bad value for the money. If you want something with a bit of a pedigree and real quality, you can easily reach upwards of $10,000 for a nice set of speakers and an appropriate amplifier/receiver.
As far as finding receivers is concerned, you'll need to make sure you match it with the number of channels for speakers you bought, as well as the recommended wattage for those speakers. For all components mentioned, it's worth going to an outlet and listening for yourself to the differences between the competing brands. It's tempting to spend extra money just because the price tag says it's better, but if you can't hear it for yourself, than what's the point?
This is a totally different topic, and for the reasons I mentioned earlier, you really don't want it interacting with your home theatre system. Home theatre is a closed system tasked with taking a single source and amplifying it for a room--pro audio live sound reinforcement is tasked with taking multiple sources, amplifying them, and doing it in such a way that doesn't cause feedback. Quality is inherently worse than home theatre, because sound reinforcement can't saturate the entire space with the content in question. Furthermore, live sound is totally different from a recording studio environment, even though there is lots of overlap in your pro audio components.
I'll describe a simple setup for an electric band with vocals. If all of the instruments are acoustic, there's really no point in reinforcing any part of the band for a home theatre-sized room. Also based on the size of the room, instruments like drumset or acoustic piano will not need to be amplified at all to compete with electric instruments.
My primary resource for pro audio is zZounds. This is raw personal preference--there are many sites like guitarcenter and musiciansfriend, but the thing I like about zZounds is the way they categorize their items--I find it very easy to find what I want and make comparisons to other similar pieces of equipment. (You'll want the "Live Sound" tab up at the top.)
- PA System (short for public address) comprised of Speakers, Amplifier, and Mixer
- Guitar Amp
- Bass Amp
1. Intentionally open-ended. You can get all of these components separately, but I really like systems with active loudspeakers (meaning, amplifier-integrated) that you can plug directly into a mixer. The popular Fender Passport systems are all of these in 1 (with an active mixer), but compromise significantly in quality. If you have an electronic keyboard, you can plug this directly into your PA instead of using a dedicated keyboard amp.
2. Guitarists generally want a bit more control over their tone, and their sound is one you'll want to separate from your main PA.
3. Same with bass, although the nature of their sound is less problematic to plug right into the PA, perhaps using a DI box, perhaps not.
4. Get a Shure SM58 unless you can't afford it. No point in buying anything more expensive.
- If no one sings and you have an acoustic piano, don't even bother with the PA--just tell the guitarists to turn it down (or put music in front of them--ha ha).
On pro audio brands
- I would never buy anything that says Nady on it (but that's just me). Behringer makes decent-quality equipment for cheap. A lot of their products are similar to those produced by Mackie, which is one of the best pro audio brands IMO. JBL makes great loudspeakers. Yamaha, as in every other industry, is consistent and good. Crown is known for amplifiers. Samson and Peavy I've never been too impressed with, but they're out there and not too expensive (Peavy's more known for guitar-related equipment, as is Fender). Hartke for bass amps? I don't really know. There are SO many opinions out there about these companies, and you can learn a HUGE amount just from browsing around the zZounds site.
People can and have written volumes just on the topic of cables for either one of these equipment families. I'm not going to bother, but please don't buy Monster Cable.