Thanks much to Zorba922 and zieglj01 for their advice and recommendations.
Hopefully my "issue" is nothing more than a bad AVR setting and/or bad memory.
If so, that let's me spend less on speakers/subs and more on other stuff, specifically the TV, which was the original focus of the upgrade.
If anyone else was curious, here's the list of speakers and subs considered based on recommendations made here and elsewhere:
Speaker Options (I'm only considering the 3.0 fronts. I'd likely sell off any surrounds and/or subs)
Infinity Sterling SS2003 + Center (used). Free to me since I already own them. No real complaints now that the center has been refoamed.
Infinity Primus C250 + C25 (used). $200 for the 5.1 set. Maybe only on par with the SS2003s, but less ancient, and easier to find replacements if needed.
Polk Monitor 60 + CS2 (used). $325 for the 5.0 set. I wouldn't take them over the Primus at this point.
DCM closeouts are creeping up in price, but seem to be a great buy. If I focused spending on speakers, I'd consider the towers.
DCM TP160S + TP160C (bookshelf + center). $165 - Guessing not worth considering over the SS2003s.
DCM TP160 + TP160C (single woofer tower +center). $240 - Guessing on par with the SS2003s.
DCM TP260 + TP160C (dual woofer tower + center). $350 - I'd like try these, but at this price, I'd probably spend $$ elsewhere.
JBL Arena 180 + 125C (refurb). $425. I think I'd go with the DCMs first at this price. Black Friday may turn up something.
Klipsch R-610F + R-52C + R41M. $500 at Adorama on the sale I missed. Maybe it comes again for Black Friday. Another sale included a Yamaha receiver for $250 more.
At this point I'll probably stick with what I have or maybe the cheap Primus if still available. I'll save the money for a sub or the TV.
Infinity BU-1. I have 2 of these now. They'll almost certainly go unless I need the money for upgrading something else.
Infinity Primus PS410/PS312 (refurb). $130/$200. Decent power, frequency response down to 25/27Hz +/3db, good reviews, friendly price, but...
They apparently have refurbs for a reason. Amps are known to overheat and die rapidly. It looks like a serious problem has been identified by the community, and there's at least 1 "fix" that I'd be willing to try at this price. Opinions on these would be appreciated.
Premier Acoustic PA-150 for $250, recommended by zieglj01 above. Looks good for the price.
Anything else is "over budget" unless I have these amounts after the TV decision.
RSL Speedwoofer 10s for $399, recommended by Zorba922 above.
Hsu VTF-1 MK3 for $399. May be discontinued. I'll call if it comes to that.
SVS SB-1000 or PB-1000 for $499. I think I can get under $450 for these.
These are "overkill" range for me, but may be interesting to others:
Hsu VTF-2 MK5 for $539.
Monoprice Monolith 10" for $550.
Monoprice Monolith 12" open-box for $680 available at the moment.