My computer line up would be:
1. PC XT Nec V20 (enough speed or slow down for xt games.
2. 286-12 mhz (use this system for faster later XT games and 286 period 1989-1991
3. 386 DX 40 Mhz (use this for games that needed a 386 machine.
4 486 DX2 66/80 DX4 100/120 machine (use this for the 486 period 1994-1996
5. Pentium 133/150 classic windows 95 *for earlier windows 95 games multi media
6. Also want to build an Pentium MMX 233, but might consider going for an AMD K6-2 build to fill the gap with earlier Pentium II area.
7. Then i have got an Pentium III 550Mhz for windows 98 se.
8 Athlon XP 2400+ build for lastest windows 98 se *installed now windows 2000 on it*
9 AMD FX6350 build with 990fx motherboard and HD 7870 GHZ for XP gaming / eventually dualbooted with vista 64 bit. or perhaps windows 7
10. Intel skylake 6700K build for windows 7 area.
For myself i think you could better go right with a pentuim III instead, then going with an older pentium II with is much slower.
Maybe you have loved the Pentium II area , then you could consider a Pentium II systeem instead.. But i would go for the fast p3 system .
For me the computers arent just an object. Its also a collection item. Id rather like to play on such an old system. Then making a more recent sleeper build, which dont breath the older days. Old computer are an experience.
~ At least it can do black and white~