Technology is constantly changing, and the thing about electronics, especially home theaters and surround sound system,is there just so much choice - how do you know you are getting your money's worth? It is to your advantage that electronics is always in a constant flux of development and your best bet is to find a surround sound system (or home theater) that is totally upgradeable.
Also if you purchase a AV receiver that is expandable - that is will take advantage of new technology as and when you want to add it, then you have the basis of a better system, that can take advantage of sound reproduction such as THX certified - you home theater is going to be outstanding! For basic surround sound you will need 5.
1 channel surround, and you can pick a decent set for a sensible price, make sure the speakers you buy is something that will last and provide a respectable sound as in the future the quality will only get better and better and you will be tempted to purchase and stretch your budget.
But top of the range speakers out today will come down in price - eventually and then you make can make the purchase without fear of blowing your budget and just waiting a little longer you will enjoy a sound far superior and much more pleasurable.
The great object of upgrading is that you can improve one component at a time and in the long run you achieve even more excellent quality that simply gets better.
Summary Go to your local electronics store and as you checkout the many options available, it is always a good idea to take your time, do not get overcome with all the bells and whistle that will surely amaze you and the choice alternatives can really be dizzying and you will be tempted to overspend.
Furthermore, make sure the components you purchase today allow you to append to your surround system in the future.