Out of curiosity, what AV receiver are you using? I ask because I'd like to try to determine the minimum impedance that it's rated for.
If you look at the spec sheet for this speaker set, I'd say that their small size really limits their capability.
Fortunately, you should be able to get improvements without spending a lot of money.
Monoprice and Dayton Audio offer budget speakers that cut some corners to give you a very low price while still sounding somewhere between "not bad" and "good"
For < $100, you could replace the front and center speakers with a Monoprice set of 2xMP-65RT bookshelf + 1xMP-C65RT as your LCR, and use your existing 4 speakers as surrounds in a 7.1 setup.
With Dayton Audio, they do have inexpensive options similar to monoprice, but some are out of stock. 2xB652-AIR + C452-AIR as your LCR, using existing speakers as surrounds.
The drawback on these is that their power handling is very low, but they'd still probably take anything that you threw at the Klipsch satellites.
At these prices, I might have suggested just replacing all the speakers, but I'm going to suggest you break your budget on a subwoofer later on.
Dayton also has the ones mentioned in the audioholic articles, which cost a bit more. The MK402X bookshelf and MK442 "center" (it can also be paired to make bookshelf speakers).
The audioholic article likes the MK442, but as a L/R pair, and not as a center channel(!).
These speakers have the problem that their impedance is only 4ohms, and some AVRs aren't rated to handle them.
Please verify the minimum impedance of your AVR before considering these.
I suggest these inexpensive speaker options because you really c/w/should replace the subwoofer, which would cost a bit more to deal with.
The one in the kit is not really very effective, but then again, it's not poorly matched with the satellite speakers it came with.
PartsExpress has several "good" budget subwoofers (you can also check out the budget subwoofer thread in the subwoofer forum) ranging from $150-$250:
The Dayton SUB-1200 and SUB-1500, and BIC F-12 and H-100ii are some popular models that should outperform the Klipsch one, and match up reasonably well with the speakers mentioned before.
If you'd like to see some thoughts on some of them, this comparison may help
You could go higher end on the subs, but it would totally overwhelm your speakers, so a mix of some of these should get you an improvement over what you have, with room to grow easily later.
Originally Posted by phollow
I can spend few hundred but not looking to spend more than that. the room is not that big it's about 15ft wide and 20 ft long. What would you recommend?