Great!
Based on your responses I've narrowed it down quite a bit.
Your best, cheapest option is to what I know, setting a quality fullrange driver in a large open baffle cabinet, such as the Telefunken.
Big and old-fashioned. But chances are you can make it look like a Scandinavian or mid-century design with a bit of oil and a speaker cover. Also works like a table meaning you can probably place a set of monoblocks on top when you get to them.
Why am I saying monoblocks? Because the speaker I an about to recommend has one weakness: Bass (C'mon, it's 6.5"). But otherwise it provides some of the best mids out there this side of the Lii Audio stuff. Of course, I'm talking about the good old Diatone Clones.
http://glowinthedarkaudio.com/diatone-p610.html
I don't know about the larger versions they also produce so I with not say anything about them. They look ragged in the frequency response but trust me, they are amazing for Jazz, acoustic, and the like. Add in a Woofer (Eminence Alpha) crossed down at 100-150 and they'll rock too. If you want more bass from the little thing then maybe do a 100-150 liter ported box with Birch Ply.
If you want more bass without adding a woofer for while, or perhaps you need an energetic presentation instead of a relaxed one more centered on Jazz and stuff, there's the Lii Audio speakers.
Problem is: They are $250 a pair.
Of course, you can go even cheaper than both. If you want to experiment there's the Visaton many begin with
For $70 a pair direct from Amazon: Not Bad. Though I have no experience with these.
For bass reinforcement down the road there's the quintessencial Eminence.
https://www.parts-express.com/Eminence-Alpha-15A-15-Driver-290-407
Though given the quality the DiaClones give, they may well deserve the W-15s (AKA 20hz in open baffle AKA Mr. Cojones AKA pretty much the best woofer you can buy)
While the Telefunken is amongst the best, I would get why it wouldn't be your cup of tea, this is why I will also include some other ideas.
https://www.lii-audio.com/dt_gallery/ https://planet10-hifi.com/fonken.html https://frugal-horn.com/index.html
Mark Audio's cannot play that loud so I don't recommend anymore. Still good-looking and great-sounding. But not the greatest out there anymore.
To be honest, the Crossover is both the most important and most expensive part of a speaker. It can make or break most speakers and chances are: You don't want to deal with it much. Widebanders these days can achieve 30-20000 (Well-applied Lii Silver 10) while blasting the house out with 1/10 of a watt. The ones I recommended do about 50-18000. 25 year olds are often down to 17000 so the bass would be where I would put most of my effort.
Just remember: After this there's no going back. The largest shortcoming will be the amplifier and while it'll soung good, chances are that there's something out there that will make it sound far better. Maybe you can later scrape around and get a better amplifier. Don't be surprised if you scour for TamRadio parts in a couple years, or perhaps you'll be building yourself a First Watt Amp from a schematic. After a while after you get your shiny new monoblocks which output an outstanding 4 Watts that you may find out cables can actually make a pretty significant difference. Then you'll go mad. Before you do so, I recommend that you begin saving for the $800 Schiit Aegir, The Schiit Sys, and a source of your choice (DDDAC, ECDesigns, Schiit, JDS Labs, etc), maybe get into Vinyl (which is not necessarily better, and by the way, the Music Hall Classic punches way above its weight). Don't go for expensive cables, make your own when you can (Duelund wire is quite good for its price).
I am not responsible for any financial insanities this will make you go through. Good luck.