Advice on speaker replacement

Great that you have components.  This allows for changes/upgrades as you go. So, how does one go from mid-fi, to hi-fi?  Been there and it has been a journey of 42 years.  I am always looking, particularly in the used sector.  I started with speakers I built and a Marantz integrated solid state, that became a Van Alstine amp, with a Bravura preamp.  Don't be happy knowing that what you have can be better.  I did a quick look on craigslist and you will find that some areas are hotter for some brands than others.  Example below, Klipsch is from Arkansas, deep roots. That said, I love the Klipsch speaker sound better with tube than solid state.  The way that I arrived at my "ultimate system", is find something that you absolutely love.  It could be an amp, speakers etc...  From there you have to match reality to sound.  Always trust your ears and screw everyone else.  Lots love Polk speakers and I can't stand them.  Love Klipsch on tubes.  Love a good LS35A with a high current amp.  There is magic to be found but you have to find first the "thing" and build around it.  Welcome to the arena, there will be blood.  Trust your ears, not me or anyone else.  Just know that it can always be better.  

Wharfdale Linton

Your system is good enough but your loudspeakers are holding you back. I’m a 68 year old deaf guy. The Lintons are just what you need/want. Stereophile solid class B loudspeaker. Good deals available with stands. Just a slight bass underline but it makes everything sound great. No overhang or bass smearing, just pure joy. It would be perfect for your system.

I owned the KEF 300 a while back, great sounding, but they are too small for your room even with a sub. My room is similar  to yours and when I went to a bigger speaker, it was much better. If you like the KEF sound, go with the bigger KEF, you can't go wrong, if you want to try something new, the Lintons/Klipsch are great speakers, but will sound different. Not bad, they are just voiced differently. 

The Bluesound Node will fit your system very well and will open a whole new world of music for you.

That's a good price for the older KEF R3, but will you also need new stands since that is an odd-sized stand-mount speaker?  Would you consider the Q750 in that price range if you like the KEF family sound?

I'm not sure what your long-range plans are, but the R3 strikes me as a couple of levels above the rest of your system.  You don't want a speaker that will reveal the shortcomings in the chain.  I would lean toward the Q750, Linton or KLH, and away from the LS 50 Meta and the Klipsh.  Go big if you have the space to place them properly.

I agree that a Node would be a good addition down the line.

I love the LS50s, but the Yamaha doesn’t have the power to do them justice. I would lean towards something more efficient. Something bigger for your room size might be wise, as the others have stated. 

I kind of think that the KEF r3 is probably the higher end of this group.

Unfortunately, I don't have any reasonable way to compare them. My previous speakers were ADS L810 II that I purchased in 1978. I'm afraid if I vacillate too long, the r3s will be gone. Re: room size. 235 square feet is not all that large. the Yamaha has 80 wpc and is 4ohm stable. Can also push 175 watts into 2ohms dynamic. Obviously not high end gear but works for me for now.

@llg98ljk 

The KEF LS 50 Meta is a beautiful-sounding speaker. The r3 has been updated to a meta version, also. The LS 50 meta is better sounding than many of the older R series. However, now the R series has been updated to the Meta; the playing field might be a little more even. 

new amp, cables, and get a thick rug, or some corner traps for reflections.

 power, get more power.

receivers, av receivers can't feed the soul

I think I've made a decision. After countless runs through available resources, I messaged KEF with several questions. To my surprise, an actual human being from KEF called me Friday and we had a great discussion about several options, and he relayed his personal experience with several products that he used at home.

I am strongly leaning towards the LS50 Meta wireless system. It is some above my initial budget but looking at it as an end game purchase, I received WAF to proceed. I know some may think it's too small for my room but he assured me that the LS50 series is more than up to the task even if I got the non-powered version and used my Yamaha receiver.

Is my decision swayed by the fact that someone from KEF took the time to call me and have a relatively lengthy conversation with me? You bet I am. That is a refreshing occurrence in this day and age.

So, the jury is in and money has changed hands. I deviated from my original plans and ended up buying a pair of KEF r3 Metas and a Bluesound Node 2i,

Being a member of the cheap "audiophile" club, I scored a pair of open box KEF r3s and a factory refurb node with an as new warranty. Overall savings of about $400.

I've been busy since the speakers arrived Thursday, so I have not had much of a chance to evaluate them other than hooking them up to make sure they make sounds. First impression, huge difference from my Q300's. Big, open sound and huge clarity. Can't wait to put some miles on them this coming week and break them in.

Nice job OP, thanks for posting.