Start scouring some places for used speakers. I picked up a pair of Polk Monitor 10's (series II) speakers (in very good shape) at a local goodwill store for $25. Just be patient and get out looking and you never know what you will find. BTW - they sound great and are currently being used in...
All are in my signature, but here they are....
Fronts - Polk LSi15
Center - Polk LSiC
Rear - Polk LSi 7 (gloss black, I removed the wood sides)
Subwoofers - SVS 25-31 CS+ and PC+
If you click on the quote in my signature, it will take you to my system showcase on the Club Polk audio...
Polk Audio LSi 7's or LSi 9's. (some prefer one over the other) The both fit into the sound that I like. Paradigm is very nice as well, but a different sound. I would say both are detailed, but the LSi's are more laid back and the Paradigm's a little brighter. Both would sound great with...
For what you are saying you want it for - I would go with the RTi series. (step up to the RTi6 if you can - some great deals out now on them.) The RTi's will give you the best sound of the 3 choices you listed. Are there other considerations than sound that should be taken into accout? Michael