Have you been ignoring me?! I posted some on the first page! lol.
Klipsch Heresy speakers are in the 100 dB sensitivity range. That is a significant boost from your current Klipsch speakers which are 95 dB. That's equal to more than doubling your amp power right there, just going with more sensitive speakers.
I found these with a quick and dirty search. First ones that popped up for me. I recommend checking your local Craigslist and search for "Klipsch Heresy speakers". The Heresy II and III are the newer ones and with a little patience I'll bet you can find a nicer pair for around 500 bucks.
Start looking up "high sensitivity speakers" on Google to see what else is out there. I think the Klipsch KG line are pretty sensitive too. When you look at specs, look for 100 dB sensitivity or better.