Amplification for Sierra-2 for 2.0/2.1 music: receiver or integrated, ~$500

[Octave]

More noobery and also me being poor. Also more verbosity. Sorry! Here:
TL;DR precis: with Sierra-2s, is there an amplification solution ~$400-700 for really good sound for mainly stereo music listening? (Preferably something you've tried yourself with Sierra-2.)

I had to decide between thread-necromancy and thread-redundancy, so I settled on the latter. I've seen some very helpful recommendations for gear that I just cannot invest in for the moment (e.g. the Parasound Halo, etc). My $500 is arbitrary and could be stretched a couple hundred dollars but really no more, and warrantied refurbs (A4L etc) are okay. $500 or less is the target, because I want to have money to put toward a sub.

Even though my needs are virtually 100% 2.0 music with the impending addition of a sub, AVRs are a persistent consideration because I'd like something with HDMI inputs and the likely ability to handle DSD conversion straight to analog, if possible. This is because the Oppo 103 won't send DSD over the coax.

(I'm told that it's silly to imagine I could hear the difference between DSD and DSD-converted-to-PCM-to-analog, and running my Oppo 103D into my little NAD C316BEE 40w class A/B integrated amp with RCA interconnects, I must admit....I can't.)

Room correction might be a feature that could prove more clearly useful. (I'm in a ~10x15 space with walls close in on one side and behind me, and hardwood floors, sitting ~6 feet from the speakers.) I hear such mixed accounts of this.

I'm operating on the assumption that a significant increase in power would provide me with better sound at the same relatively low volume. (Using NIOSH SML on an Iphone 5 with its internal mic---don't laugh!---it seems that I rarely ever peak above 83db(A), and rarely that loud.) As one argument that I keep encountering is that watts are _not_ just watts, but depend on the quality of power supply, I can't assume that I'm right about even this; but let's say that ~80w/channel would be the minimum increase in power that I would be looking for?

I've been looking at a number of options, but some recommendations from personal experience---within the constraints of budget, and closer to $500 than to $700 would be ideal---would be most appreciated.

Some things I've been reading up on, and most of these as "antiquated" refurb options:
1. Integra 70.2 (for Audyssey XT32, for DSD, for allegedly having the HDMI board issue now solved)
2. Pioneer SC-81 (to try a Class D, though for the moment the power ratings seem troublingly couched in that "1kHz" business, with the "20 Hz – 20 kHz" measurement given as "VSX Model Power Rating Only"...still can't determine the meaning of that)
3. The usual options among the other big brands: Yamaha, Denon, Marantz.
4. Searching for integrated amp options at equivalent prices---e.g. the Yamaha S series---but it's hard to know how superior the two-channel playback sound is.

If the DSD-to-analog scenario is patently snake-oil nonsense at this point, this makes a lot of options more interesting.