Heya,
If you want great sound for life, or at least 20 years or so, then start with two great 2 channels speakers. Then add a sub (if you are into movies); a good sub. Then as you expand, add a center. The center should be
significant if you're into theater, it's where most of the info will come from, so it needs to be great (and that means likely
big too). Lastly, add two surrounds. They're the least useful and least meaningful in the 5 channels. You could slowly build a really great system to round out a few decades and have great quality.
If that's not an option and you just want decent budget speakers for as cheap as possible, then look to the Dayton B652 Air. You can get them in pairs. Get three sets and use one for the center channel even and the last one, since they're so cheap, can be "for parts" in case something goes wrong. They're big 6.5" woofers with pretty good tweeters for their cost. They can dig pretty deep too for what they are. And add a 10 to 12 inch sub to compliment by handling 80hz down to 30hz basically (the budget options above by Monoprice are about all that will fit this bill for cost or Dayton DIY kits).
Dayton Audio B652-AIR 6-1/2" 2-Way Bookshelf Speaker with AMT Tweeter PairDayton Audio B652-AIR 6-1/2" 2-Way Bookshelf SpeakersPure Dimensional SoundGet the power and punch for your home audio system from the compact Dayton Audio B652-AIR book shelf speakers. Featuring pristine high frequency...
www.parts-express.com
(and I will argue, do not bother with the horizontal center version in this Dayton AIR range, they're small drivers, not worth it, I've used them and measured the horizontal center and its not as good as just using another standard horizontal bookshelf version with the bigger driver)
Very best,