I'm getting older and have accumulated quite a few amps over the years. They all seem to be my favorites (I have issues). I have various topologies of SS and tubes. I enjoy them all.
Here are some of the ones I really love in no particular order and none are uber expensive:
- Eddie Vaughn's Carina (single-ended EL-84 done right)
- Nelson Pass's Amp Camp Amp (class A all the way)
- Frank van Alstine's AVA Ultravalve (ST-70 on steroids)
- B&O Ice Power AS 1200 (effortless power class D with manners)
- Antique Sound Labs Wave 8's (punchy and great fun)
- Gabe Velez's 300B (single-ended euphonic bliss)
- Chinese FU-32 board (thanks Ed)
There are a few I'm sure I'm missing, but those are the main ones that come to mind at the moment.
I've used them all with the Horns except for the Icepower amp because I'm not wanting to replace those pesky Fostex drivers.

If I had to choose one of the above, I'd have to give a nod to the AVA Ultravalve with EL-34's It can take 3 or 4 different output tubes to suit you system, room, etc. It has gobs of tube power and makes the Horns dance. Besides the Carina, it's the only one I haven't been temped to modify. After six years I haven't even looked inside. That says a lot.

I have to say that I have a few preamps as well and the Truth makes all those amps sound like gold.
So, what do y'all like? I'm always interested in what others find to be excellent.
PS, I often look at the Upscale Audio site and the entertaining videos Kevin Deal creates to promote his line of products. I can't afford that stuff, but wonder if there are gains to be made. I'm pretty content these days, but I do wonder...