There has been a spate of posts recently by people asking what 5.1 system to get for $1k. If you want a nice sounding system and are trying to get a surround sound setup for $1000, here is my advice: DON'T.
Get a 2.0 or 2.1 setup instead. Trust me, if spent wisely, it will sound much better than the same amount spread over more speakers. Quality > quantity. A couple of good speakers and a good subwoofer can give you a sense of realism and depth that a whole gob of cheap speakers can not, regardless of the application, whether home theater, games, or music.
I am not even saying to start with a 2.1 setup and build it up over time. I am saying 2.1 is all most people really need for a nice full sound, and by diluting the quality of speakers for a larger quantity, everything suffers. You lose a lot more than you gain. But yeah, it does make for an easy upgrade path over time, but that is not why I am recommending it.
Let's talk about skipping the center channel. The center is certainly the most important speaker after the front left and right, and subwoofer. It usually carries the dialogue, and its chief value is in making the dialogue less weighted to the left or right if you are sitting off-axis with respect the the optimum viewing position. It's nice to have, but it is not worth lessening a full, dynamic sound for. The left and right can carry the dialogue pretty well by emulating the center in what is called a phantom center. Your AVR will have this feature and it works pretty well. If your budget is modest, do not let the center channel eat into the budget for a good left, right, and subwoofer. The center isn't THAT special.
A properly setup front left and right can generate a really good soundstage that a center speaker doesn't really contribute much towards, at least if you aren't sitting too far off to the side. To repeat, it just anchors the dialogue and certain sound effects to the center of the sound stage, and the value in that is in off-axis viewing, not so much in on-axis viewing. On-axis, a good left and right setup can mimic a center very well (and has been doing so ever since sound engineers started working in stereo).
Let's talk about the surround channels, the rear left and right. DEFINITELY don't let surround speakers eat into a modest budget. They carry maybe 10% of the sound mix, but even that much seems high. They mostly just emit ambient sounds such as chirping birds, city traffic, rainfall, etc. Occasionally they will be used for an effect sound like a plane flying past, or maybe a helicopter or something like that. They are not at all essential. You don't lose much by not having them. They add slightly more immersion, but an aggressive use of them makes them a distraction more than anything else. I could easily live without them. A good, properly well setup two channel system can generate a very enveloping sound which surround speakers can only add a little bit to. Do not trade depth for breadth.
Now let's talk about the subwoofer. This is important, and this is what I see sacrificed far too often to get 3 or more speakers. Good subwoofers are awesome. Good bass is amazing and vital to a great, realistic sound. The subwoofer has the hardest task to do; sound reproduction is about moving air, and the sub has to move the most air by far. The sub should consume most of your budget. In a strict $1k budget, the sub should eat up AT LEAST 600 of that, if not more. That basically only leaves you with enough money for two halfway decent speakers. But the good news is that is all you need for a great sound.
A lot of people want a 5.1 or 7.1 system, and really they are just ticking off checkboxes. They want the idea of having a surround sound system, but they don't care about the actual sound. Don't be one of those people, they are terrible people in my book. If you want to be an OK person in my book (and you should), you need to want a good sound, not just an X amount of speakers.
Let's put it another way. If I were to put together a good 2.1 system for $1k and I had you or anyone else compare it to what would be considered a good value 5.1 system, I am betting at least 4/5 people would say the 2.1 sounds better. Now as the budget increases, diminishing returns set it, and you might as well go for a surround sound system, but the heart of the speaker system is the front left and right and sub, and you have to get those right first if you want a really good sounding system.