Beginner guide to speaker systems?

So recently I've been wanting more and more to have a decent 2 channel setup at home for everyday listening. I kind of miss sharing amazing music moments when I'm using my headphones but I know pretty much nothing about hifi.

Can anyone give me a quick rundown? I see terms like SET thrown around and I've been trying to get an idea from the general interweb but it seems like such a massive rabbits hole and all the guides seem very out of date. Reading about the Feb meet impressions with the EAR 834 / HE6 made me wonder whether I could combine my audio systems and I've actually had a bit of a look around for that amp to no avail (second hand).

If I was looking for a really great sound are there any more affordable tube amps that anyone could recommend? Speakers? The ones purrin has look great but I'm not sure if i could build the enclosure. Lets say I had a $3000 US budget for amp / speakers where would everyone turn?

Apologies for the ramble I'm just a bit lost. For reference I currently have Gungnir Multibit > V2 > HD800S.