For a 5-channel system you should spend most of your speaker budget on the front three speakers, the Left & Right front speakers, plus a Center Channel speaker. Sub Woofers will cost more, but you should wait and see what your front 3 speakers sound like by themselves. The two rear channels speakers are much less important and you can save money on them. Some of the choices you should make depend on how much floor space you have.
Wait until you have speakers selected before you think about electronics. Base your choice primarily on how much power the speakers need and what kinds of audio or video hook ups you need. Don't worry over other features, as they will make much less difference than speakers.
There is no need to spend $30k or even $15k for an excellent 5 channel system. As an example, consider
Philharmonic Audio. It sells speakers only through the internet – no dealers anywhere. If the Maryland/Northern Virginia area is an easily driven distance for you, you can hear these speakers, and even pick them up yourself. For a high priced system, you should consider:
BMR Tower Pair – a pair of top of the line speakers for $4,200. Their bass performance is so good that sub woofers may not be needed.
or
HT Tower Pair – similar performance to the BMR Towers, but with a smaller footprint, for $4,500.
HT Center Channel – will go well with either of the above towers, for $1,400. If you order this speaker along with either of the towers above, you get a $200 discount.
For rear channel speakers consider either of these (below). It depends of what kind of space is available, and just how you'll mount them. Either of these can be mounted on walls.
True Mini Monitor – $380 per pair
Ceramic Mini Monitor – $850 per pair
All this adds up to no more than $6,550. Shipping will add to the overall cost.
There are other good speakers available, but don't pay more. There are annual shows of commercial audio products, including the brands sold only by Internet Direct. Your location should make one of them a good choice to hear a wide variety of speakers.