it's kind of tough to use something --that retro--..
I think one of them wolfie 8400 (D0) or 8700 builds is the bare bottom for USEABLE retro..
their single thread rating is as high as 1700 w/ full overclock..
That's very usable..
One of my x220 which I use all the time with a 2520m does 1700 single thread..
A pentium g3258 build could also be fun.. I got 4 of them, 4.6 4.7 4.7 4.8ghz. benches 2800 single core. Very good for the starcraft.
x220 you say eh? That would be a good "value proposition". Put a new battery in there.. run light weight distro (arch) ... dosbox + some productivity software that is light weight.. just vim and tiling wm.
I would like to have a machine that is OFF the internet... just to focus on writing and thinking.
For nostalgia, I would like to have some REALLY old hardware.
But being on the internet... makes me start look at things.
When I really want to write, I still do it on paper.