The HK 3390 is a very capable receiver. So are NAD integrated amps starting with the 316 BEE all the way up. One of the things that make them so capable and robust is that they are all 4 Ohm rated, high current amps. AVR's have their place but the reality is their power supplies are compromised in the low to mid range models and cannot put out their rated power. This is well known, even among AVR advocates but often when they are recommended, there are caveats, such as "when used with 8 Ohm speakers and at moderate listening levels" and "not driven to high volumes", or "when operated within spec",etc.
What if someone wants to listen at high volume? What if someone wants a higher spec? Also, I know the OP is thinking about Klipsch that are 8 Ohm and highly efficient, but what if he changes his mind? What happens if he gets the Klipsch and decides to upgrade? What happens if he hears a pair of 4 Ohm speakers and decides these are the ones for him? If this happens, the HK or the NADs are ready to accommodate now.
I have a NAD 316BEE in a secondary system in about a 275 square foot room. It is driving vintage 6 Ohm nominal, 4 Ohm minimum ADS L520 speakers and it does a remarkable job allowing me to get these speakers up to significantly high levels. It has never clipped, over-heated or gone into protection mode. At only 40 wpc, it is a true 40 wpc and generates the high current needed from its fairly large power supply. I would recommend this amp or the HK over an AVR at twice the price.
Marantz PM15S2 LE, Oppo BDP-103, Simaudio Moon 100D DAC
VPI Traveler V2 with an Ortofon Rondo Blue and Simaudio Moon 110LP, Technics SL-1400 with an Audio Technica AT-14sa and Pro-ject Phono Box S
Dynaudio Focus 260's, Rel T-1 and a Panasonic TC-P54S1.