I haven't heard the Reference series from Klipsch, but their cheaper speakers are very harsh to my ears. The Polk TSi lack some clarity but they're decent speakers.
FWIW, if you decide to go with TSi series speakers, head over to eBay and buy the Monitor series from Polk Direct instead. The TSi 500 is really just the Monitor 70 in a new cabinet, and you can get a pair of Monitor 70s from Polk for about $310.
Also look at the Infinity Primus series. About the same prices as the Polk Monitor series, but seem to be much more highly regarded. Look on Amazon for great prices.