The underdogs do get my attention, but not exclusively.
With XT I'm spoiled: most of them already run at 8 or 10MHz with full blown 640kB RAM. Some have MFM/RLL drives, some XTA, some property ones, but with exception of my Model 30s they are fairly fast for their generation.
I have this nice little 286 system: IBM model 30-286 which runs at only 10MHz and has only 1MB of ram. I prefer it over my 16MHz 286 which is almost twice as fast in checkit benchmark.
At 386 I only have a DX40 Machine running, ET4000AX and 8MB. I still have to replace the good old Connor hard disk for a faster one. Quite high end for its generation.
For 486 systems I'm fond of my nameless DX/2 at 66 MHz and mediocre Cirrus graphics card. It's about our sweet spot of 486, although I upgraded the RAM to 32MB.
I do have some more 486s, mostly DX/2 66 and recently got myself a (stable) DX50 board. If they are not fast enough I'll go for socket 7.
Socket 5, 7, S7: I have a nice K6-3+ 400 running, 256MB Ram and for now a Geforce 4 graphics card. Might be swapped fo a V3 3000 somewhere this year. This I call "almost the ultimate super 7" computer.
Besides that, I have several S7 boards and computers laying around, but I think they are a little bit less interesting. Except for my S5 Compaq 😀
For Pentium 2 / 3 I have a 440BX system with Katmai 450, no need to go faster on slot 1 because there's where my IBM Netvista P3-866 takes over and shreds anything the 450 struggles with. Also underdog Celeron doesn't really do it for me...
Netburst... Yeah, I got some of these but hardly ever touch them.