The PSB's are a natural comparison to the Paradigms, and if you must buy new, both are excellent brands for the money. I have helped several friends put together systems using both Paradigm and PSB, and they are all quite happy. The Studio 100 v.3's are a standout speaker at their price, IMHO. However, if you might consider going used, I myself would prefer a Thiel system. Much better imaging, soundstage, etc., but still dynamic and full-range. If it were me, I'd budget $1,000 (maybe more) for a decent sub, pick up a pair of used CS3.6's or maybe 2.3's for the L/R, and that should leave enough for three SCS2's or maybe even SCS3's for center and surrounds. Presuming that you have amps able to drive them, I would suspect that a Thiel system like I have outlined would be a noticable improvement over Paradigm or PSB. B&K and Martin Logan are also very good suggestions, but of course it ultimately comes down to personal preference.
Tom.
Tom.