I have played SEIV on four different computers... an old laptop, an ancient desktop, an upgraded ancient desktop, and the computer I'm using right now.
Laptop:
1996 Acer Laptop, 11" LCD screen
Pentium I 166MHz, 64MB RAM, 14400 baud modem, 4x CD-ROM, 1GB HDD
Windows 95
Ancient Desktop:
Pentium I 133MHz, 16MB RAM, 28800 baud modem, 4x CD-ROM, 1.5GB HDD
Windows 95/98 (upgraded when 98 came out, so played SEIV on 98)
Ancient Desktop (upgraded, by me):
AMD K6-2 400MHz, 128MB RAM, 56k modem, 16x CD-ROM, 1.5GB HDD (same one as above) and 5GB HDD
Windows 98SE
This Desktop (it, too, qualifies as ancient, got it summer 1999):
Athlon 700MHz, 128MB RAM, 56k modem, 48x/16x/4x CD-RW, 28.6GB HDD
Windows 98SE
...
All of you may now begin feeling sorry for me, and begin donations to the "Get Will a Decent Computer Fund"
But I am planning on building another one sometime this summer... so far it looks like Athlon XP 2400+, with Soyo MB, Via chipset, 512 DDR-RAM, DVD/CD-RW combo, 40GB HDD, GeForce4 card w/ 64MB. And I know about the AMD heat issues, I got that covered (case has 6 fans).