Just off the top of my head:
Intel 486DX2, 8mb ram. Needs a NIC, I have three spare ISA ones here untested.
Intel Pentium 133Mhz, 128mb ram. Needs NIC and case/psu but I have spare (the yellow wire on the psu for this one is actually blue, never seen that before, old AT psu not ATX).
Intel PII - hmm looks like I might have thrown this one out.
Intel PIII 350Mhz? 256mb ram. Needs NIC I have spare
Intel PIII 1Ghz 256mb ram. Needs NIC I have spare.
AMD skt A/462. Tested two days ago, needs new mobo, eveything else assumed working.
Intel Prescott P4 skt 478, 2.4ghz I think?. 3Gb ram, 6800gt agp

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skt 1155 celeron, 8gb - my server
skt AM3+ AMD Phenom 965 Black edition, 8gb ram - main pc
I'd still be keen to play some games on the 486 lol. Need to get another hdd for it, I have a CF card but the BIOS can't see anything larger than 504mb drives and I'm reluctant to lan on the 20yo drive it has in there. I was hoping to burn an eeprom with xtide and install that onto the boot rom of one of the spare ISA network cards I have so I can support larger drives.